former industry term
for a quality of silver plate equivalent to 3 Troy ounces of silver per
gross of teaspoons; also known as medium.
(a-bal-o’ nee) Pearl from an abalone, usually showing the
iridescent colors characteristic of the interior of its shell.
Any material used for
grinding, emery, oilstone powder, carborundum, levigated aluminous
oxide, etc.; or for polishing (which is just a finer grade of grinding),
fine abrasives like diamond powder, diamantine, sapphire, rouge, etc.
abrasive points -
points of various shapes, mounted on 3/32” shanks and used in flexible
shaft machine for metal removal.
abrasive wheels -
diamond encrusted wheels in various binders, used on mandrels in
flexible shaft machine for metal removal and finishing.
absorption band -
interrupting the spectrum as viewed through a spectroscope. The
specific locations of these interruptions are characteristic of some
gemstones and thus can be used in gemstones identification.
alternating current; electricity which reverses direction at a stated
rate (cycles) per second- for example “60 cycles A.C.”. It must be
employed for demagnetizers, and for electric clocks that are driven by
public service current. See also D.C.
A gaining rate
superimposed on the regular rate of a time-piece, particularly of new
marine chronometers during their first year’s service. This
peculiarity is explained to variously by authorities to be considered
well understood. It disappears naturally as the balance and its spring
continue in use.
- Trade name for
refractory material for holding parts in position during soldering.
A condenser for storing electrical energy, used in
electrical clocks and watches.
- (Ac’ cu’ tron’)
Brand name for the sonic timepiece introduced by Bulova Watch Co. in
October 1960. A turning fork replaced the traditional balance
wheel and hairspring, its vibrations being converted mechanically to
rotary motions and transmitted through a gear-train to the hands.
acetin acid -
A form of vinegar
used for purposeful erosion of steel parts such as broken screws from
watch parts. Also, an adhesive for some plastics.
A liquid used as an
ingredient in solutions for cleaning watches, and as a solvent for
resins and fats. It is well to avoid using acetone near an open
flame, as its vapor is highly flammable.
A colorless gas,
C2 H2, highly flammable. Used with air or oxygen in a torch for
soldering, welding and melting metals.
- (a’kro-ite) A
varietal name, like rube-lite, indicolite, etc., for colorless
such as “achromatic sapphire” for white sapphire.
acid bottle -
designed container for dangerous acid used in jewelry work, and for
blue-remover acid for watch work. The body of bottle is at least
as wide as high, to prevent upsetting; the stopper fits with a ground
glass joint, and has a glass stem, reaching almost to bottom of bottle,
for applying acid.
acid gold -
A process whereby a design is acid etched into the body
dinnerware, then painted with liquid gold which is fired on and
acid test - 1.
the karat-quality of gold. This includes a black porous stone
slab, a set of test needles with assorted karats of gold on the tips;
and a bottle of nitric acid. Gold to be tested is rubbed on the
stone; beside its “track” is rubbed another with one of the test needles
of known karat. Acid is applied over the two tracks. If the
needle track stands and the other one disappears under the acid, a lower
karat needle is tried next, and so on, until the acid ha same effect on
both tracks; the final needle karat is then known to be the karat of the
gold tested. See KARAT. 2. Diamonds. Boiling
diamonds in concentrated sulphuric acid to remove color coating.
French for “steel,”
stamped inside Swiss made watch cases of stainless steel.
teen) An early European name for corundum, especially a dark grayish
brown variety from India.
Greek word originally
meaning “incombustible.” with reference to iron, iron alloy, gold,
sapphire and carbunculus; probably first applied to diamond by the
romans in the 3rd Century B.C. The Romans used diamonds from India as
cutting tool; valued them above all other substance not only for their
rarity and supreme hardness but also for their magical powers as an
A zinc arsenate found
in some abumdance in Mapimi, Duranga, Mexico. The yellow-green
crystal clusters have been used in some bits of hand-crafted jemerly
which exploit the natural crystal shapes.
The acting portion of a gearwheel tooth or pinionleaf that extends
outside the true diameter or pitch circle.
ruby - A
local misnomer, like most locality modifications preceding the name of
the gem, in this case for a red Australian garnet.
A substance that
causes materials to adhere to each other as, cement, glue, epoxy,
A German name for a
silicified diabase or porphyry, and best regarded as an impure
adjusting rod -
A long rod with
sliding, adjustable weight used to obtain maximum, uniform mainspring.
Result of work
done on watches to improve accuracy of timekeeping after manufacturing,
by altering the forms and relations of parts, differentiated from
REGULATING. The usual adjustment are to temperature, positions and
isochronism. See REGULATING.
A bluish or white
sheen resulting from the internal reflections from twin lamellae.
The same as “schiller” or labradorescence, but this refers specifically
to the light-colored feldspar or moonstone. See ADULARIA; LABRADORITE;
- (ad-you-lare’ ee-a).
A pure, colorless to milky potash aluminum silicate feldspar which
occurs at its best in the Alps. However, most moonstones, the
variety with the schiller color, are found in Ceylon. See
APHROSELINE, CEYLON OPAL, WATER OPAL, ICE SPAR, FISH EYE, WOLF’S EYE,
GIRASOL, SILVER STONE.
A local American
misnomer for pale, sky blue aquamarine.
An attachment to a balance to compensate for errors in
temperatures not corrected by the balance itself.
African emerald - 1.
Misleading name for green fluorite. 2. Greenish yellow emeralds
from Transvaal. The rich green emeralds, found in 1957 in Rhodesia
near Sandawana, are called by the letter name.
African jade -
A compact green
and white massive grossularite garnet from the Transvaal. Also know
as South African jade and Transvaal jade
African tourmaline -
term for a light, blue-green brilliant tourmaline, of any origin.
A soft, compact,
yellowish or reddish brown amorphous mineral, an alteration product of
other rocks which is widely used by the Chinese for cheap carved
objects. Also called pagodite. The word is from a Greek word
meaning “an image.”
A turquoise varietal
name, given is 1806 to a conchoidal turquoise occurring in a porphyry or
lava. Named for Demetrios Agaphi, who examined the Persian
microscopically crystalline, variegated chalcedony. It may be
banded, irregularly clouded or have visible impurities as in
moss agate. A very common variety of quartz coming at present
principally from Brazil. Locally abundant in the West. It is
one of the many varieties of quartz. Most commercial German
agate is artificially. (See ALEPPO STONE, CARNELIAN, EYE AGATE,
IRIS AGATE, MOSS AGATE, SARD, etc.). Used in horology for knife-edge
suspensions for clock pendulums, and for the jaws of fine poising tools
for watch work.
agate jasper -
intermediate between chalcedony and agate. It formerly was called
“jaspe fleuri” by jewelers and came principally from Sicily.
agatized wood - Wood petrified
through cell by cell replacement by jasper; that from Arizona is often
brightly colored and attractive. Petrified Forest National
Monument in Arizona is a preserve where the logs may be seen in place.
“hands,” inscribed on some Swiss watch case caps to show where to apply
key to set the hands.
An effect on the motion of parts of timepieces, particularly balances
and pendulums, caused by their passage through air, which tends to
impede their movements.
air-gap - The distance between
a wheel or balance and the closest object is a coil or magnet.
a jour - The name for an open
setting, so that the underside of the stone may be seen. Originally
restricted to French, but now a widely used term.
- A porous coral used
in ancient times in jewelry, especially West Africa and Samoa.
Name later applied to substitutes such as pearls, coral, rock and glass.
alabandine ruby -
for almandine garnet, both of which names derive from Pliny’s name for a
source in Asia Minor, Alabanda. The name has also been applied to
alabaster - A massive,
fine-grained variety of gypsum, hydrated calcium sulfate, usually
white, yellowish or pink. It is often used for carving and older
clock cases as it is very soft and easily tinted. It is found at
alalite - Local misnomer for
diopside arising from the name Val d’ Ala. This locality in
northern Italy is known for its garnets as well, but few gems are found
black diamond -
Misnomer for quartz.
albite - The white sodium
feldspar common in rocks and sometimes found in crystals which show a
bluish schiller, like moonstone. Albite moonstone is another name
sometimes applied to stones of this type.
Liquid used for
cleaning watches and jewelry, and as a solvent for removing cements and
for making liquid cements. Grain alcohol is more costly and
better, where small quantity is needed. Wood alcohol or denatured
grain alcohol is much cheaper, being tax free, and is used where greater
quantity is required.
diamond - Misnomer for quartz.
stone - An
eye agate, believed in parts of the East to be of value in treating a
kind of sore known as an Aleppo boil. See CYCLOPS AGATE.
- Trade name for the
best quality of turquoise coming from the world’s oldest known deposits,
on the west coast of the Sinai Peninsula. Also called Egyptian
alexandrite - A variety of
chrysoberyl which because of its unusual absorption changes color in
different lights. It is green in daylight and wine-red in most
artificial lights. It was found originally in the Urals and since
in Ceylon, Brazil and Tanzania, and was named in honor of Alexander II
of Russia. Color changes vary in different stones and most good
“night-stones” and apt to be very dark in daytime. Now made
synthetically, like emeralds, for costly substitutes. The so-called
synthetic alexandrites of the past, widely sold for years al low prices,
are actually synthetic sapphires (rarely spinels) colored by vanadium
and not true synthetics in the accepted sense. They should have been
called simulated alexandrites, or alexandrite synthetic corundum.
A chrysoberyl with
parallel inclusions, cut cabochon so that it shows a light streak, which
changes color in different lights. SEE CAT’S, ASTERISM, ALEXANDRITE.
all chromatic -
the coloring by minor impurities of stones, which, if pure would be
colorless. Few stones are Indio chromatic, that is, colored by essential
band - A
watch strap made of alligator, crocodile or such simulated material.
alloy - 1.
A metal to
be melted with another to form a compound metal with qualities suitable
for some particular use. 2. the compound metal resulting from
melting two or more metals together, whose properties and melting point
may differ from those of its components. Derivation. Through the
erroneous fancy that Fr. aloi was = a loi ‘to law,’ the word,
meaning originally simple combination, union,’ come to be used specially
of the mixing of baser metal with gold or silver in coinage, so as to
bring it to the recognized standard, and hence of the standard itself. -
Oxford English Dictionary.
by wind or water, in which heavy minerals are often concentrated.
Diamonds and gold are frequently mined from the type of deposit. See
(al’man-deen) A purplish-red, iron aluminum garnet. Once called
almandine or almandite, the name is derived from a source known as
Alabanda in Asia Minor. Almandite has been dropped in accordance with
current usage, the ine is now preferred by mineralogists. Common
obfuscating names include Ceylon Ruby, Cape garnet, vermeille garnet.
Syrian garnet, and, from ancient texts, carbunculus alabandicus.
See ALABANDINE RUBY.
remarkably fluorescent amber from Olanesti in Rumania. See DELATINITE.
diamond - Misnomer
alum - Aluminum
ammonium sulphate, used in powered or lump form, dissolved in water, for
rusting out broken screws imbedded in watch plates so as not to be
mechanically removable. Keeping the solution hot speeds up the
rusting process. Alum was also used for reducing perspiration of
the hands of workmen, by rubbing them with a lump of alum; or by washing
the hands in alum solution.
name for spinel, as an imitation diamond, from the composition, a
An effective, hard abrasive made in various
grades and grain size.
An alloy of mercury with another metal or
metals. Amalgams of gold are used in some processes of gold
plating. An example of gold amalgamation in the common one where
in a piece of gold jewelry becomes accidentally saturated with mercury,
which makes the gold white and brittle. The mercury may be driven
out of the gold by repeating heating of the piece.
amaryl - Name
given by H. Michel to a light green synthetic corundum.
amatrice, the name coined for the mixture of green variscite with
chalcedony and quartz, cut cabochon, and mined at Stockton, Tooele
County, Utah. “American matrix” is the origin of the name.
amazonite - Or
Amazon stone, a green variety of potash feldspar known as microcline and
frequently found in pegmatite dikes and usually white or pink.
Found in Virginia, Russia, Colorado, Brazil and Madagascar in abundance,
locally elsewhere. An old name, referring to the Brazilian deposits.
amber - A fossil
resin. Mineralogists have separated many resinous compounds which
may be grouped under this name. It is the preserved gum of
coniferous trees and mostly comes from and near the shores if the Baltic
in East Prussia. Burma, Romania, Sicily, New Jersey and Canada
have produced similar resins. Often insects which were entrapped as the
gum exuded have been preserved and their shells are to be seen in
finished pieces of amber. See ALMASCHITE, BURMITE, BALTIC AMBER,
BECKERITE, BASTARD AMBER, BONY AMBER, CLOUDY AMBER, COPAL, DELATINITE,
FOSSIL RESIN, FROTHY AMBER, SEMI-BASTARD AMBER, SUCCINITE.
applied to amber chips and flakes which have been pressed under heat to
build up a solid mass. Also called pressed amber.
cut brilliant -
proportioned in accordance with the calculations published in 1919 by
mathematician Marcel Tolkowsky, “ the only aim being to obtain the
liveliest fire and the greatest brilliancy.” The figures, girdle
diameter considered as 100%: table diameter, 53%; crown thickness,
16.2%; pavilion thickness; 43.1%; table-to-culet depth, 59.3% plus
girdle thickness; angle of crown facets, 34.5°; angle of pavilion
facets, 40.75°. Also called Ideal Cut. American Gem
Society grades of cutting (1975) are defined in terms of degree of
departure from such proportions and finish. See BRILLIANT; CUTTING
GRADE; EUROPEAN CUT; TOLKOWSKY, M.; MORSE, HENRY.
Gem Society -
A selective, non-profit professional
organization of jewelers of the United States and Canada, seeking to
advance gemological knowledge, guide ethical practices, and enhance the
public image of the industry; founded in 1934 by Robert M. Shipley.
See REGISTERED JEWELER; CERTIFIED GEMOLOGIST.
jade - Misnomer for a compact grass-green variety of vesuvianite, a
calcium aluminum silicate, occurring in California and also known as
A term used in other countries to describe a
live-spindle, spit-chuck lathe with flat, horizontal bed.
Misnomer for a garnet. Prefixes of this
sort preceding name of a more precious stone, such as emerald, ruby or
diamond, almost without exception indicate an attempt to create a demand
for a less valuable stone by deceiving the purchaser into thinking that
the relationship to the true gem is more than superficial. It
cannot be too strongly decried.
Watchmakers Institute -
association of watchmakers organized in June 1960 in Chicago, a merger
of the Horological Institute of America and the United Horological
Association of America.
A purple variety of coarsely crystallized
quartz. The origin of the color is unknown. It is a popular
gem and comes in many shades, the deepest, often called Russian or
Uralian amethyst, being the most desirable. Almost all amethyst comes
from Brazil and Uruguay today. See AHLAMAH, BAHIA AMETHYST, BISHOP’S
STONE, URUGUAYAN AMETHYST.
instrument to measure the amperage of a current in a watch or clock.
Doublet made of lumachelle. See
ammonia - A liquid
used as an ingredient of various solutions for cleaning watches and
jewelry. The variety of ammonia usually meant is formulas for
cleaning solutions is “household ammonia,” a weaker solution of ammonia
gas in water than other commercial ammonias
Microwave amplification of simulated radiation.
compound used to oxidize copper, silver and low karat gold.
amorphous - “Without
form,” and means that there is no regular internal arrangement of the
molecules, as opposed to crystalline, in which there is such an
arrangement, though fracture or cutting may have removed any external
indication of that structure.
The unit of measurement of electrical current
passing though a circuit whose resistance is one ohm.
(am’fib-bole) A group of minerals whose compositions are related, all
being complex silicates, and most of which have only mineralogical
interest. White, green, yellow, or brown nephrite, one of the
minerals included in jade, is the most important of this group from a
gem standpoint. Blue crocidolite is an asbestos-like member of the
group which is important because it has been replaced by quartz in
asbestos mining areas in South Africa and Australia, and the preserved
fibrous structure shows in the “tiger-eyes” cut from this material.
See NEPHRITE, HORNBLENDE, TREMOLITE, PYROXENE.
Measure from the point of the rest, the outermost swing of a balance,
pendulum or oscillating body.
graphometer - An
electronic instrument which indicates the amplitude of a timepiece on a
metered scale. Synonym: amplitudoscope.
A charm worn by the superstitious to ward off
ill, or accomplish some desired end.
An almond-shaped or rounded nodule from an
amygdaloidal basalt. Such as volcanic rock has the small original
trapped gas bubble cavities filled with mineral deposits, such as agate,
subsequent to the solidification of the lava, possibly during weathering
of the upper levels, by precipitation from downward percolating
A timepiece with dial, hands and numbers or
markers, its total display being analogous, or comparable, to a 12-hour
(an’na-tase). An unusulas form of titanium
oxide, very rarely used as a gem. It strongly refracts light, is
brown to blue in color, and has been found in cut-able stones only in
the Alps. It is questionable if stones of this have ever been cut except
- A term
describing the escapement used in most clocks, the pallets resembling
the flukes of an anchor.
Ancona ruby -
The French (Swiss) term for the lever of a
watch or clock.
“echappement a’ancre”. See LEVER ESCAPEMENT.
(an-da-loos’ite). An interesting aluminum silicate which is sometimes
cut as a gem. It crystallizes in the orthorhombic system, which means
that it is referred to three different axes at right angles to each
other. When viewed in these different directions it has a
pronounced pleochroism, from greenish to yellow to reddish brown.
This color difference shows best in stones which are emerald-, oval or
cushion cut. It is found in rolled pebbles in Brazil and Ceylon.
A variety known as chiastolite contains many black impurities which are
pushed aside into definite positions by the growing crystal, resulting
in a pattern of a white cross or regularly spaced white areas in a black
background. It is found in many places, Massachusetts, California, and
Australia among others, and is used as a gem locally. The name
andulusite is sometimes erroneously applied to brown tourmaline.
See STEALITE, HOLESPAR, CROSS STONE, LAPIS CRUCIFER.
(an’dra-dite) A calcium-iron garnet; red, yellow, brown, green or black.
Topazolite is pale green or brown; demantoid a brilliant green and the
most valuable of the garnet group. See BOBBOWKA GARNET, TRANSVAAL
JADE, SUCCIN-GARNET, VIRIDINE.
A thin air-evacuated metallic box, used as a
barometer or altimeter to test barometric pressure; in horology, to test
barometric effects on timekeeping. Also used is some “perpetual
A geometric figure formed by two intersecting
straight lines; the extent of arc of an oscillating body such as
balance, pendulum, vibrating reed, etc.
Not isotropic, meaning that light does not pass through in different
directions at the same speed. Anisotropic substance have the
property of breaking light up into rays vibrating in different planes
and traveling at different speeds. Crystalline substances not
belonging to the cubic system have this property. See DOUBLE
REFRACTION, SINGLE REFRATION, ISOTROPIC, LIQUID CRYSTAL DISPLAY.
An ornament of gold or silver or other metal,
worn around the ankle in the same manner as the bracelet adorns the arm.
Process of heating metal which has become
compact and brittle. The heating removes the brittleness and
renders the metal soft and malleable, so it can be worked. 2. In
glassware manufacture, the reheating and gadual cooling of glassware to
reduce the stresses and strains which are the chief cause of breakage.
The balance of a timepiece whose shape is that
of an uncut ring.
A term used in electroplating to denote the
positive pole in a plating bath, to which is attached a bar of metal
which is partly electro-deposited on the article to be plated. The
latter is attached to the negative pole, or cathode.
- (ah-nom’ ah-lus) Double refraction in a substance that is usually
singly reflection, such as diamond, garnet, glass, or synthetic spinel,
occasioned by internal strain. During polariscope examination, the
extinctions tend to be irregular.
Antilles pearl -
real pearl, but a mother of pearl sphere cut from the iridescent shell
of the Turbo snail, at whose apex there is a thick place which will
permit the cutting of such a sphere. Also known as an oil pearl.
antimagnetic watch -
composed of metals not affected by magnetic influence. Rule 4 of
the Federal Trade Commission’s Guides for the Watch Industry, amended
1970, says a watch may be called “antimagnetic” if its daily rate is not
change more than 15 seconds by exposure in an electrical field of
60 Gauss for five seconds in a horizontal position.
anti-oxidizer - Any
preparation used for preventing formation of an oxide scale on work
undergoing soldering or other heat-treatment. For soldering jewelry,
many trade-marked anti-oxidizers may be bought; or a preparation of
half-and-half boracic acid crystal dissolved in grain alcohol may be
painted over the work, and allowed to dry, before soldering. In
heating steel for hardening, a coating of moistened soap applied before
heating, is a good antioxidizer. See HEAT SHIELD.
reproduction - Jewelry.
An obvious copy of the original but modernized to satisfy both
contemporary taste and nostalgia for the old. b. a
scrupulous copy, perhaps almost indistinguishable for the original.
A gem shape; an elongated stone with sounded
A process whereby metal objects ate chemically
treaked so that they take on color or patina associated with age.
Silver and copper will gradually turn back upon immersion in a solution
of liver of sulphur (potassium sulphide). Gold may be darkened by
plating in a “Black Chrome” solution.
Antwerp rose - A manner of cutting diamonds popular in the 17th
Century but now seldom if ever used. It is a rose cut with 12 to
24 facets, the upper facets being very flat. Also called the
anvil - 1.
solid base which may be struck. 2. The fixed and of a
measuring gauge. 3. In chronographs or repeaters, the part
against which the hammers act.
Smoky-hued glassy prelatic obsidian nodules found in partially hydrated
volcanic glass deposits. As cut stones, they resemble smoky quartz, but
are singly refracting and much softer. Abundant near Superior,
phosphate, the mineral which is number 5 in the Mohs hardness scale.
Often transparent and highly colored, it makes an attractive, but little
appreciated, gemstone for specialists. Hues include yellow, green,
violet and colorless. Too soft for many uses, they are, are,
nonetheless, occasionally used in jewelry; the yellow Mexican stones are
the most abundant. Also known as ASPARAGUS STONE and MOTOXITE.
An opening or “window” in a dial or case to
allow the display of a feature such as a date, day, moon phase, etc.
Greek name for adularia, meaning the splendor
of the moon.
The time indicated by a sun dial. Due to
the eccentric orbit of the earth, high noon differs as much as 16
minutes from clock time. Clocks indicate an average, or “mean,” of
Ornamental work or enrichment made separately and applied, fastened or
mounted on another metal.
Appraisal - official valuation document made by a certified
gemologist and expert in field of diamonds and metals.
A local (Cape May, N.J.) name for reddish yellow quartz pebbles.
apyrite - Name
given to peach-bloom colored tourmaline; a needless complication of the
name for a light blue synthetic spinel.
Sky-blue to greenish blue beryl.
Aquamarine chrysolite is a misnomer for a greenish yellow beryl.
Aquamarine emerald is a misnomer for doublets made of colorless beryl
cemented by green glass. Aquamarine topaz is a misnomer for bluish
topaz. Aquamarine triplet is the same as an aquamarine emerald.
A mixture of nitric acid and hydrochloric
acid, used for testing high-karat gold by the stone-and-needle
(touchstone) method; and for dissolving gold and platinum. An
average proportion is three parts hydrochloric acid and one part nitric
acid. Care must be taken in mixing these acids, to avoid damage my
splashing; and not to breathe the chlorine gas that arises. Named
by medieval alchemists because it would attack the royal metals,
platinum and gold. See ACID TEST.
Decoration in the Arabian style; the features
are geometrical outlines, flowers, fruits and foliage, combined and
grouped; on clocks or watch-cases or dials, marquetry with scrollwork.
Misnomer for white sapphire.
on-ite) A form of calcium carbonate and an important constituent of the
pearl. Also widespread as a non-gem material. Though less
common than calcite, it is a differently crystallized variety of the
same compound. See CALIFORNIA ONYX, MEXICAN ONYX.
A part of a mechanism that rotates; or that
turns in pivot bearings while holding something that turns, as a pallet
arbor, balance staff, pinion on a wheel, etc. A stem (winding) arbor and
a barrel arbor are examples.
Part of circumference of a circle; the path of
motion of a pendulum or of the balance of a watch.
Clock dial with upper part in form of a
half-circle; the type helps fix age of old long-case or mantel clocks.
Arch dials were introduced about the year 1700. Prior to then,
dials of such clocks were square with a straight edge at top. The
arch at first was decorated with ornamental engraving, marker’s name,
etc.; later it accommodated mechanical features like moon’s phase disc,
or equation work.
The detrimental action of an electrical surge
across a gap between two contacts such as in an electrical clock watch.
Arizona diamond -
Arizona ruby -
such names, a misnomer for garnet.
Arizona spinel -
Arkansas diamond -
especially bad misnomer for quartz. In the case it is more than
ordinarily to be condemned, since genuine diamonds are also found in
Arkansas, and there could well be confusion.
A whitish gray stone used as a fine abrasive in
solid or powdered form to prepare graves or pivot for polishing.
That part of an electric-motive device in which
force is induced as in a clock, watch or motor.
Late 19th and early 20th
Century style of art that found its way into jewelry. It is
generally depicted as curved, flowing, assymetrical forms, recurring and
intertwining as leaves, flowers and insects.
artificial stone -
See IMITATION; SYNTHETIC.
Yellow-green transparent apatite, originally
from Murcia, Spain.
The analysis of ores, bullion and alloys to
determine the proportion of precious metal content. Tests accurate
to within one-part per thousand, made by the British Assay Offices of
articles made of karat gold, may be obtained from scrapings as one
milligram (30/1,000 oz).
Office - 1.
the Treasury Department; the U.S. Assay Office in Denver tests ore
samples; that is New York assays and reclaims gold and silver for
government agencies and performs “umpire” assays of bullion for private
owners 2. In certain foreign countries, governmental agencies
place their mark on precious-metal fabrications.
Asscher - diamond shape named after the world-renowned cutter
Joseph Asscher; square with cut corner.
To put parts of a watch or clock together to
make up a complete timepiece.
Asteriated or asterism, all refer to a property
possessed by some gem stones when cut cabochon or when viewed in
transmitted light, if reflecting the light as a star, or surrounding the
light source with radiating rays. Star sapphires are best known,
but star garnet, beryls and rose quartz are known; in the latter it is
very common. It is caused by an internal arrangement of microscopic
needles of an included mineral or of tubular cavities parallel to the
shape the mineral has in nature. When all run in one direction
they create an “eye” as in cat’s eyes.
An artificial product, much like aventurine
glass, with blue flecks in dark ground mass.
astronomical time - 1.
time. 2. Mean solar time shown on a dial with hours
numbered from 1 to 24 instead of from 1 to 12, or noon to midnight and
midnight to noon. See SIDEREAL.
A misnomer for malachite. Atlas pearls,
spar, or stone in a fibrous, colorless, red, blue, or green calcite,
which, when polished, has a silky luster. It can be dyed to
resemble a cat’s-eye. The name is also applied to the still softer
gypsum of the same character, also known as satin pear.
A “perpetually wound” clock with torsion,
suspended balance wound by changes in temperature.
In horology the units of pound per square inch (14.7 ft. at sew level)
used to denote the test units of water-resistance to which watches are
A highly precise electrical clock with resonant
frequencies of atoms or molecules of a gas such as ammonia or cesium.
Designates an ore or a metal containing gold.
Australian ruby -
Misnomer for garnet.
Watches and clocks with moving figures of
people, animals, etc., an art highly developed during the 17th,
18th and early 19th Centuries. Examples of
it are in nearly all watch and clock collections. Automata of
largest size are on some ancient architectural clocks in Europe.
center punch -
powered punch used for marking locations on metal for accurate drilling
additional provision on the usual compensating balance, mostly on marine
chronometers, to lessen the “middle” temperature error.
power in a watch or clock to keep the balance or pendulum and hands
moving during winding or in an electrical clock, the reserve power
to maintain timekeeping until power is restored.
(av-ven’tyour-een) A name with many applications. Used with
quartz, it refers to a green variety of quartzite which contains flakes
of green mica. Aventurine feldspars, such as sunstone, contain
flakes of hematite which reflects light in certain positions. This
is usually reddish brown in color. Aventurine glass is a very
widely used product, now less so then formerly, which contains crystals
of copper in a brown ground mass. The name originated through the
accidental Italian (aventura-chance) discovery of this effect. This
must be about the only instance when the jewelers have applied the name
cheap artificial product to a better natural stone. Also known as
goldstone and widely sold as a local product. See CHRYSOLITE,
A basis for weighting things other than jewels
and precious metals. The unit is a pound containing 7000 Troy
grains. The Troy pound contains 5760 grains. In buying old
silver, when one’s Troy scales will not accommodate the large quantities
involved, use avoirdupois weight; then convert this to Troy weight,
allowing 14.583 Toy ounces per pound aoirdupois; and .9115 Troy ounce
per ounce avoirdupois.
name for abalone.
See AMERICAN WATCHMAKERS INSTITUTE.
End thrust or pressure on the ends of pivots of
A complex mineral, a borosilicate of aluminum and calcium with iron and
manganese, which is rarely cut as a gem. Usually it is clove-brown
in color, though yellow and greenish shades are not unknown, Dauphiné
in the French Alps supplied the most typical rough; some have been cut
from Mexican material. It is rarely seen in the trade. The
name refers to the wedge-shape of the natural crystals.
A crystallographic axis is an imaginary line
passing through the center of an ideal crystal, and parallel to the
intersections of the principal faces. The crystal systems are
based upon the axes, and range from three equal axes at right angles to
each other in the isometric system, to three unequal axes at oblique
angles to each other in the triclinic system. See CRYSTAL. The
theoretical center of motion of an arbor or other rotating object.
of) stone - Also called bluestone. A soft, compact-grained
stone used in the form of a flat lap, or slip, with water, to flatten or
smooth out imperfections in watch parts, etc., made of brass or other
A local misnomer for zinc carbonate, smitsonite.
for wedding rings, or other jewelry made to be set with stones, the
settings are said to be “azured” when each has the hollow for the
pavilion of its stone formed in a square; the space below the girdle of
the stone having form of a truncated pyramid.
A confusing name which has been applied to
quartz pseudomorphs after crocidolite (tiger eye) in which the original
blue color has been preserved. Also called sapphire quartz and
siderite; no more desirable terms then the above.
A blue basic copper carbonate ore of copper,
often associated with, and even altered to, the more stable green form
known as malachite. Commonly cut into bright blue or
blue-and-green cabochons. Soluble in acid and reatively soft,
azurite must be handled with caution. See MALACHITE, CHESSYLITE.
invalid name for chrysocolla-saturated chalcedony. See CHRYSOCOLLA.
back cock -
The bridge of a
timepiece supporting the rear balance or another pivots.
Play or freedom of motion; as when a wheel in a train is pushed
backsurge current -
In an electrical timepiece, current sent through a coil
generates a magnetic field around it. When the current is stopped,
the field collapses in the opposite direction.
Baffa diamon -
Misnomer for quartz.
bagos de arroz -
Literally “bags of
rice.” A Brazilian term for long and flat rough diamonds.
(bag-ett’) 1. A rectangularly-shaped small diamond or other gem
stone. 2. A very small rectangular bracelet watch.
(Originally, a French term describing a small watch worn as a ring).
- A rectangular-shaped stone with rows of step-like facets. If the
baguette's two long sides taper inward, it is called a Tapered baguette.
Baguettes in long, thin cut rectangles are often used as enhancements to
a lager center stone, or on a watch bezel.
Diamond - diamond saturated with graphite inclusions
(bah-ee’ah) Amethystine quartz from Bahia, Brazil.
The locality is noted for the large size and purity of the material, but
dark shades are rarer than in Southern Brazilian and Uralian stones.
emerald - A
name now of no special significance, since there are several emerald
sources in Bahia, Brazil, yielding stones with widely differing
characteristics. Some, as in Salininha, are vanadium-pigmented.
However, most, like those of Carnaiba and Conquista, are perfectly
normal emeralds by any standards.
A finding, connected to pendants or stones worn as pendants, etc. to
accommodate a chain, cord or thong.
(bake’el-ite) A colorless plastic made from phenol and
formaldehyde, and named for its inventor, Dr. L. Baekeland. It can
be dyed any color and is often sold as an amber imitation. It can
be readily identified by the formaldehyde smell which results when a hot
needle is pressed into it.
The part of a watch
or chronometer whose vibrating, governed by its spring, perform the
actual timekeeping that is indicated by hands on the dial. See
BIMETALLIC, CUT, INTEGRAL, MONOMETALLIC, PLAIN, STAFF.
balance assembly -
A group of parts in a
timepiece comprising balance, staff, spring, and roller.
balance arc -
The extent of the
balance amplitude. See AMPLITUDE.
balance chuck -
A lathe chick with
boxlike opening to hold the balance and allowing only the pivot to
extend through a tiny hole in the face for adjustment.
balance cock -
The bridge housing
the balance hole and cap jewels of a timepiece and secured at one end as
compared to a true bridge, which is secured at both ends.
balance coil - An electromagnetic coil situated on a balance.
balance magnets -
mounted on a balance of an electrical timepiece.
balance screw -
One of the screws
threaded into the rim of a balance to supply an adjustable mass.
balance screw fixture -
A scaffold upon which
a balance rim is placed to allow changes or adjustment to its screws.
balance spring -The hairspring on a balance.
balance stop lever -
The pivoted lever to stop the balance on a stop or hack
(bal’as) A term used in Brazil for a gem fragment of zonal
tourmaline from which the outer layers have been removed to show the
clear kernel. See BALLAS.
Balas ruby -
A misnomer for red
spinel. From rubin Balais from Balascia, a synonym for
Badakshan, Afghanistan, which furnished the best stones in the
Balbach process -
Method of refining
silver containing small amounts of gold. Anodes of impure silver
are electrolyzed in an acidified silver nitrate bath; pure silver is
deposited on a carbon cathode. Same as Thum or Tham-Babach
Bal de Feu -
Trade name for
man-made strontium titanate.
ball bearing -
An arbor bearing
containing a ring of steel or jewel balls.
ball clock -
A clock whose
apparent timekeeping or winding is governed by guided steel balls
falling in tracks.
ball jasper -
Masses of round,
brown to red jasper ranging from nut to head sizes. Formerly found
with iron concretions in Breqau. Probably an equivalent of the
California poppy stone.
Name said to be
applied to round American Freshwater pearls by the pearlers.
Rough diamonds in rounded shapes, unsuitable for cutting as gems, but
very valuable for industrial uses. They have a confused,
intergrown internal structure which makes cleaving through them
impossible, and consequently, they are tougher them usual diamonds when
used as tool tips.
Baltic amber -
Amber from East
Prussia and neighboring beaches. Most amber in commerce in mined
in this locality.
A stem is said to be
baluster-shaped when it has a swelled boss in the shaft. The term
occurs with cups and candlesticks.
band - 1.
A ridge or belt,
usually plain but sometimes ribbed or decorated, about the main body of
a vessel such as a coffee pot or a tankard.2. A wedding ring.
3. A watch strap or bracelet.
banded agate -
Agate which has
formed in a series of bands; most agate in trade is of this type.
The bands are characterized by slight differences in pore spaces and
grain size, usually the banding is exaggerated by differential dye
absorption. Almost all banded agate in the trade is artificially
colored. See AGATE, ONYX, SARD, etc.
banding jasper -
Jasper showing a
banding similar to agate, often brightly colored, and coming from many
localities. See RIBBONSTONE.
B & S gauge -
Standard American gauge used for measuring thickness of wire and sheet.
Used more frequently by silversmith than jewelers who prefer the
micrometer or douzieme gauge.
A solid or hollow non-flexible bracelet, a wire bracelet.
banking - 1.
Any solid or
adjusting stop for escapement to limit its movement. 2. Roller
jewel striking outside of fork due to excessive motion of balance.
Also called REBANKING.
banking, magnetic -
watches, a permanent magnet draws and retains the indexing fork to a
banking, over -
The result of the
pallet fork’s accidental movement to the opposite banking, thus
preventing the roller jewel from entering the fork and thus stopping the
banking pin -
acting as banking for the angular movement of the pallet.
banking screw -
An eccentric screw
projection allowing the pallet banking to be adjustable.
banking to drop -
Adjusting the banking
of an escapement so that the fork drops off a pallet jewel without
further angular movement (without slide).
bar jewels -
Archaic European term
meaning jewels for train-pivot bearings.
bar movement -
A design of watch
movement in which pivot-bearings are all in bridges, so that all train
wheels are visible. Also called “bridge movement.”
setting - Similar to the channel setting, it is a circular band of diamonds or
gemstones that holds each stone in by a long thin bar, shared between
A term for the pallet
cock or bridge.
Barion cut -
square-shaped mixed cut a for diamonds, introduced in 1971 by Basil
Watermeyer of Johannesburg, South Africa; named after his wife Marion,
with the first letter of her name replaced by that of his. A full
emerald cut crown is combined with a brilliant cut pavilion, modified by
four half-moon facets parallel to the square girdle, and with four
pavilion facets that form a cross when seen through the table. It
rivals the round cut for brilliance, surpasses the round cut in weight
A square barion cut diamond has 61 facets, excluding the culet.
barium glass -
A highly refracting
glass once used to imitation gems. Batium increases both the
relative weight (specific gravity), and the reflecting power
A white srystalline
compound used as a ceramic transducer in ultrasonic cleaning devices.
bark finish -
An attractive finish
produced by engraving somewhat wavy lines, roughly parallel to each
other. It is most often formed with an eccentric knife-edge
cutting wheel in a flexible shaft machine. Watch cases, bracelets
and dials are often ornamented in this way. So called for its
similarity to tree bark.
A kind of decorative
engraving on metal, produced by a geometric lathe. See
barley twist -
decorations on clock cases.
(ba-roe’da) Term used by one ring manufacturer for glass cut
like diamonds and backed with foil to increase their brilliance.
barometric error -
The deviation of a
timepiece due to changes in altitude or barometric pressure.
shape of gem or pearl.
- (ba-roke’) Pearl of irregular form
The hollow short cylindrical box in which a mainspring is housed.
In a “going” barrel, the arbor turns only in winding the spring; teeth
on outside of barrel turn the center pinion. In a “motor” or
safety barrel, the teeth are on a separate (main) wheel and this turns
with the arbor as the watch runs, the barrel remaining stationary and
turning only during the winding of the spring. See FUZEE,
barrel arbor -
Arbor on which the mainspring barrel turns and which turns for winding
the mainspring, in going barrels; or which carries the pivots of the
main wheel in motor barrels.
barrel, hanging -
Barrel whose arbor is
supported at one end, used in thin watches.
barrel plating -
electroplating in rotating barrel. See ROTATING BARREL, TUMBLING.
barrel shape -
A gem shape with flat top and bottom and rounded sides.
(bah-ret’) 1. An ornamental bar, with a pin and clasp mounted on
the back, to be worn in the hair. 2. A file with
teeth cut on lower side, and its back uncut and of ridged cross section,
also known as a safety back file. 3. The pallet
(bazz’a-nite) A name which has been given to a black compact
fine-grained quartz which is used for testing precious metals by
observing the color of the streak made upon it. See TOUCHSTONE,
bascine - (bah-seen’) The form of joint between the center and the back or
bezel of a pocket watch case in which the joint when closed is
invisible, without a ridge or bead.
(bass-kule’) Describes the French form of chronometer escapement
with a pivoted arbor and spiral spring to mount and operate the detent,
instead of the English form with a one piece spring to perform the same
bascule setting -
A watch winding
mechanism set into a pivoted rocking bar to shift the wheels into
winding and setting phases.
base metal -
Any non-precious metal.
A fancy setting of
various shapes with numerous sides piercing that provides a basket work
or lacy appearance.
- (bahs-tie) An enameling technique whereby transparent enamels
are placed over chased or engraved designs in metal and fired. The
variations in thickness produce interesting gradations of color.
bastard amber -
A cloudy amber.
See BONY AMBER, BLUE AMBER, AMBER.
bastard file -
A rough, course cut
(bass-tite’) A variety of greenish serpentine with a patchy sheen. It
is used in small art objects. The luster comes from the coarse
crystal grains of original mineral bronzite, which has been altered to
the serpentine. See SCHILLER SPAR, VERDE DE CORSICA, CALIFORNIA
batata roxa -
Brazilian name for
the brownish-violet colored tourmaline which is usually called rose in
baton figure, hands -
Hands or figure
resembling the flat, short, straight Roman sword.
A unit of electrical
energy composed of two or more cells; however, common usage refers to
even a single energy cell as a battery. b>1. Watches.
Watch batteries are composed of a top anode (-) with its insulating
seals, crimped into bottom cathode (+) can. The anode material is
zinc amalgamated with pure mercury or silver oxide, topped with a
barrier and electrolyte. When the (-) and (+) are “loaded” by the
demands of the watch, electrons flow from the (-) to the (+).
Batteries designed for LED, LC-digital, analog and sonic watches are
seldom interchangeable; hearing aid batteries should never be used in
watches. Most watch batteries are designed to meet their normal
requirements for more then a year. 2. Clocks. Clock
batteries are of similar compostion, but their shapes may very depending
upon the space available.
battery, rechargeable -
Any form of electrical cell whose depleted energy may be restored by
charging from an outside electrical source.
battery strap -
The metallic bridge to secure the battery to the movement.
Bavarian quartz cat’s-eye -
actinolite inclusions that give to cabochon-cut stones the eye-like
reflection streak. Formerly found near Haid and
Treseburg-Bodetal in the Harz. See HAWKEYE.
bayonet case -
case whose back is secured in a fraction of a turn in a sturdy
bead - 1.
A narrow semi-circular moulding such as an astragal. 2. A form of
stone cutting suitable for stringing, necklaces, etc. 3. A hollow
metal sphere used in necklaces, etc. 4. A circular or elliptical
stone worn as part of a neckchain or bracelet. 5. One of a number
of fasteners raised from the background metal to secure stones.
See BEAD SETTING.
bead setting -
A method of diamond setting in which the stones are set flush in a strip
of metal. The stones are held by the beads which are raised by the
diamond setter from the surrounding metal.
beading - 1.
A variety of
gem-stone setting in which the clamps over the edge of the stone are
formed by pressing into the metal a punch which has a hemispherical
hollow, which forms the bead. 2. A detail of ornament on jewelry,
watch cases, etc., consisting of a row of hemisphere beads pressed into
beak - That part of a chronograph return-to-zero lever that contacts the heart
bearded girdle -
cracks extending into a diamond from the girdle, caused by excessive
speed in bruiting. The girdle looks fuzzy, lacks the normal smooth,
or girdle fringes - The outermost portion of the stone, called the
girdle, can develop small cracks that resemble whiskers during the
polishing process. The bearding can sometimes be removed, if not too
dramatic, with slight re-polishing, and if the weight allows.
bearer - 1.
Holes in the framework of a timepiece movement in which pivots run.
The bearing of pivots which run at the greater speeds, in “jeweled”
watches, are jeweled to reduce friction and wear. 2. The groove
or shoulder in which a stone is fitted in a piece of jewelry.
beat - 1.
“Out of beat” is a condition in which a balance or pendulum has uneven
extant of motion on the two sides of its line of centers, which is
indicated by the uneven sound of the beats. When this is
corrected, the balance or pendulum is said to be “in beat”. 2.
Beats per hour, or “the train” of a watch, are the number of impulses
given to the balance per hour by the escapement, such
as 21,600, 19,800, 81,000, 16,200, etc. This number is fixed by the
total gear ratio of the train between center wheel and escape wheel,
inclusive, and must be matched by the beat-number of the balance
beat tool -
A tool to twist the
hairspring collect to effect the “in-beat” condition.
An optically abnormal olive-green zircon, found in Ceylon.
A variety of amber
without commercial value.
beef-blood ruby -
Said to be a name for
a color grade of ruby, of deeper red than the pigeon-blood.
An atized coral in
which the white coral skeleton stands out on a flesh-red back-ground.
Found near Aden and elsewhere. Erroneously called backite.
bed - The flat main part of a lathe body upon which the head and tailstock and
attachments are mounted.
Wax produced in beehives used in jewelry making as a lubricant for wire
drawing, sawing and, occasionally, drilling.
beggar beads -
Necklaces of hand-cut quartz stones made so inexpensively in India
that even beggars can afford them. Some strands are graduated beads of one
stone and shape. Other combine many shapes, sizes and colors of jasper,
agate, carnelian, moss agate, bloodstone and chalcedony.
Behr loupe -
A magnifying loupe in
which the lenses are mounted on a hinged clamp to be attached to a
spectacle-frame, so that the loupe lenses may be swung away from in
front of the spectacle lens, when not being used. See LOUPE.
Beilby layer -
A thin layer of vitreous amorphous material on the surface of polished
stones, other then diamond, caused by melting and flowing during the
polishing process; named after Sir G. T. Beilby, who expressed the
theory in 1921.
Bek process -
A patented method of encasing a base-metal article with continuous
precious-metal coating. After being electroplated with gold, platinum,
or a gold alloy, the article is subjected to a heat treatment to being
about diffusion between coating and basis metal, to modify the
composition, color and wearing qualities of the coating, and through
annealing and precipitation hardening to control the physical properties
of the base metal.
belcher setting -
A type of ring mounting with the setting claws formed in the shank of
bell - A gem shaped similar to the tulip shaped, but with central peak.
bell chuck -
A split, stepped
concave lathe ollet used to hold a variety of disc-shaped objects such
as wheels, rings, and coins. Usually, the largest diameter of this
chuck well exceeds that of its main body.
An alloy of copper
and tin, a variety of bronze, which is one of the best materials for
laps for polishing staffs, pivots, etc., used with diamantine, rouge,
bell pearl -
bell punch -
A staking punch whose
end is concave, bell-mouthed, used to contract metal parts.
bell standard -
The base or boss upon
which the bell of a timepiece is fixed.
A variety of
moonstone found in northern Russia near the White Sea.
bench shears -
heavy duty shears,
fastened to a bench. Used for cutting heavy metals.
bench key -
A flat, round metal
disc with numerous radial prongs in the form of watch or clock keys of
bench vise -
A small accurate vise
used on a watchmakers bench.
Bangal anethyst -
Misnomer for purple sapphire.
barium titanium silicate. It is blue in color and resembles a
sapphire, but is much softer (6½ in hardness) and shows, in the
dichroscope, a strong color contrast, blue and white. Gem material
is found only in San Benito county, California, hence the name. It
is an attractive, but little used gemstone, and if more common would
un-dubitably be more popular. An expert can recognize this gem by
a violet color almost always to be seen in the reflection near the
girdle, a result of dispersion over double that of sapphire.
bent top -
A rounded top cutting of a deep stone, in which the girdle follows the
curve of the top.
C6 H6, flammable,
volatile coal tar solvent.
A liquid used for cleaning thickened oil and dirt from watches and
clocks, a product of distillation of crude petroleum.
(bear’il). An important mineral, the ore of beryllium and one which has
several gem rep-resentatives. It is a beryllium aluminum silicate,
which crystallizes in six-sided prisms. The gem varieties all have
special names such as emerald, aquamarine, morganite, golden beryl,
heliodor, vorobievite and goshenite. See BIXBITE, AEROIDES,
CHRYSOBERYLLUS, CHRYSOLITEM, CHRYSOLITHUS, HYACINTHOZONTES, AMETHYST-BASALYTINE,
DAVIDSONITE, AQUAMARINE-CHRYSOLITE. It comes in many colors and shades,
has a hardness of about 8 and, except emerald, is a durable stone.
It is rather low in reflective power and consequence depends for its
beauty upon color rather than brilliance.
beryl cat’s-eye -
A variety of beryl which contains the parallel inclusions which create
the cat’s eye effect in a finished cabochon gem. See CAT’S-EYE,
beryl triplet -
See AQUAMARINE TRIPLET.
A trade-name applied
to synthetic rose inel, colored with chromium oxide.
A very hard elemental metal, used as an alloy in metals for various
uses in horology and jewelry work.
A sodium beryllium phosphate. The colorless crystals found in
Maine are sometimes cut as a gem for collectors.
- (be-rill’o-scope). A filter for viewing gems to aid in their
determinations. See CHELSEA FILTER, DETECTOSCOPE, EMERALD FILTER.
bevel cut -
Stones with a large table and the edges beveled by a single facet; the
bottom may be cut normally, or it may be the same as the top, in which
case it is known as double bevel cut.
bevel gears -
Pairs of pinions with leavers at angles to transmit power at a right
angle; for example, in stem-winding work in watches.
(bezz’el). 1.The upper part of a gem, the crown facets, namely
those above the girdle. Also spelled bezel, and bizel. 2. A
continuous groove of a form to fit a stone in a piece of jewelry, with
metal at top of groove burnished over edge of stone to form a setting.
3. The grooved ring forming part of a watch case, around the
dial, into which the watch crystal is fitted. 4. In silver
hollowware, the projecting flange or lip inside a cover or lid fitting
the latter to the body of the vessel proper.
bezel cutter -
A tool to cut or mill the under-cutting in a bezel crystal.
- Also called top main facets; four of the eight four-sided
facets that alternate with the four similarly-shaped top coner or
quoin facets between the table and the girdle of a brilliant cut
diamond. Some cutters and many jewelers apply the term bezel facets
to all eight facets. In Great Britain all eight are called
kite facets; in Scandinavian Diamond Nomenclature, upper main
See BRILLIANT CUT.
B.H.I. - British Horological Institute.
bias - In
an electrical timepiece, a steady voltage placed in series with a
A wire with two sets
of winding as used in electronic watches with both sensing and impulsing
Billston show watch -
watch used by poor to affect status of watch ownership.
bimetallic balance - A
compensating balance, with laminated spilt-rim made of brass outside and
steel inside. See BALANCE.
binding wire - The soft iron wire used for binding together parts of jewelry etc.,
while being soldered.
nautical time invented by Morris Tobias of Wapping in 1812.
bipolar circuits -
magnetic poles as used in electrical timepiece.
bird’s eyes -
pearl term for slightly imperfect pearls with dark rings.
bird’s eye quartz -
A colored jasper containing colorless quartz spherules.
bird wing pearl -
Wing-shaped baroque (usually fresh-water) pearl.
(bye’ree-frin”gence). A technical word for the separation by a
doubly refracting crystallized substance of single rays of light which
have been broken into two rays and made to vibrate in two planes at
right angles to each other, moving at different speeds. The amount of
separation may be great or small, but in only in a few cases, such as
peridot and zircon, is it sufficiently strong to be visible to the naked
eye. When pronounced, as in those gems, a doubling of the edges of
the back facets, as seen through the table, is easily recognizable; if
weak, it may often, on colored stones, be detected in a dichroscope,
which separates the two rays and shows their color differences, or by a
polariscope. See ANISOTROPIC, DOUBLE REFRACTION, INTERFERENCE
Stones which have been selected as appropriate and lucky
for wear by people born in the respective months; mounted in rings,
earrings, and other jewelry. The list, adopted by Retail Jewelers
of America Inc. in 1912, follows: Jan., garnet; Feb., amethyst; Mar.,
aquamarine or bloodstone; Apr., diamond; May, emerald; June, pearl,
moonstone or alexandrite; July, ruby; Aug., period or sardonyx; Sept.,
sapphire; Oct., opal; Nov., topaz or citrine; Dec., turquoise or zircon.
By Federal Trade Commission rule, it is unfair trade practice to use the
word “birthstone” or the name of any precious or semi-precious stone as
described of a synthetic, imitation or simulated stone unless preceded
by the word “synthetic”, “imitation”, “simulated” or other word of
like meaning to disclose the fact that it is not a natural stone.
biseau case or movement -
movement or case.
An elemental metal, much used in alloying solders to
produce a solder that will melt at extraordinarily low degrees of heat.
The second-bit is an enamel watch dial is the circle of enamel
soldered or cemented in the main dial and forming the second-dial.
center-bit in a “double-sunk” dial is the piece cemented or
soldered or soldered inside the hour-circle and forming the center of
bitellos - Brazilian term for large diamonds.
biting-in - A term used in etching to describe the action of acids on
metals such as copper, silver, or steel, on those parts which are not
covered with a resisting substance. See ETCHING.
bivouac watch -
A special-feature watch that shows altitude and barometric pressure,
used by mountaineers and parachutists.
- A cultured pearl, originally non-nucleated, grown in a
fresh-water mussel in the vicinity of Lake Biwa, Japan.
bixbite - Name given to small pale red crystals of beryl which are
found in topaz pockets in portions of the Thomas Range, Utah. Recently
more interesting because of the discovery of deeper red and larger
crystals of this type in the neighboring Wha Wha Range, mostly embedded
in rhyolite, and even now capable of yielding only minute stones of a
rich red hue.
- A lumpy diamond with overly deep pavilion. When
viewed face-up, the reflection of the latter in the center of the table
are black. Also called dark centered.
black coral - A black coral-like substance, but distinct from precious
coral. Divided again into true and false black corals depending
upon the animal responsible for its formation. The luster is horny
to pitchy. The hardness 2.5 to 3, and the color ranges from dark
brown to deep black, but rarely is light brown to pale yellow. Comes
from Hawaii, Malay Archipelago, the Red Sea, and a little in Bermuda and
the Mediterranean. It is used in art objects, beads, bracelets,
knife handles, etc., especially in the Orient. See ACCARBAAR.
- (der’moe-graff-ism) Literally, “black writing on
the skin;” a phenomenon sometimes reported by wearers of precious-metal
jewelry. Caused by relatively hard chemicals in cosmetics, medicated
creams, lotions and toothpaste- such as zinc oxide, titanium dioxide,
ferric oxide, calamine and pumice- lodging on the under side of rings,
bracelets, necklaces, and pins. Often with hardness 6, such
particles abrade the jewelry metals (gold or silver, hardness 2),
depositing a fine, black metallic powder on garment or skin. The
particles look black because they are too small to reflect light.
Stainless steal or chromium are too hard to abrade; high-karat gold
alloys, being soft, smudge more readily than do harder, lower-karat
alloys. See NICKEL DERMATITIS.
- A term used for truly black diamonds, for carbonado, and
- Almost unknown in nature; produced in Idar-Oberstien, West
Germany, and elsewhere by warming chalcedony in a sugar solution for
several days or weeks; then placing the stones in warm sulphuric acid,
which reacts with the sugar, precipating free carbon. The color is
permanent; no tests exist to determine the artificiality.
black opal -
A precious opal of a dark hue, blue, gray, or black (red to
grey-brown in transmitted light), in which the color play stands out.
See PRECIOUS OPAL, OPAL.
black pearl -
Natural Oriental pearls from grey to almost black.
black-treated opal -
A granular type of whitish Australian opal, black treated by a variation
of the sugar method used to transform chalcedony into black onyx. Such
stones are almost opaque and do not fluoresce under ultra-violet; with
magnification, carbon can be seen along the fissures. Certain Mexican
opals, blacked by smoke and heat, have a dark brown to black body color
with vivid color flashes.
Black Velvet -
Trade name for an electrochemically produce deep black
finish on gold jewelry.
bleaching - 1.
The routine treatment
of pearls and cultured pearls with peroxide when first finished, at
which time they may be tinted pink, blue, or black. 2.
Gemstones. Some brown tiger-eye is bleached light brown, and then
perhaps recolored in an unnatural hue. Turquoise, dulled by skin-oils,
has been bleached to its former attractive hue. 3. Ivory.
Ivory is sometimes bleached to remove oils absorbing in handling.
Blemishes - The term blemish is used when the diamond has scratches
or marks on the external area of the stone.
blister pearl -
A one-sided pearl attached to the shell, not a true free
Large cleavage fragment of diamond.
The initial shaping of a brilliant, putting on the first 17
or 18 facets which are later divided in brillianteening.
blood coral -
Name applied to precious red coral.
blood drops -
Water worn red spinel pebbles.
blood enamel -
An ancient imitation coral.
blood jasper -
Heliotrope or bloodstone.
Same as heliotrope, formerly known as hematite.
blow pipe -
A small mouth-pipe for blowing a blast-flame for hardening
steel, soldering, ect.
A mechanical generator of compressed air, either of bellows
or rotary pump type, for supplying a blast-flame for
heat-treating and soldering metals is horology or jewelry work. See
blue amber -
Trade-name for light-colored, highly valued bastard amber,
with something of the bluish color of diluted milk.
blue chalcedony -
Chalcedony which is naturally, or artificially, blue in
color. The naturally blue is somewhat dull and grey, fairly well-colored
pieces are known in the Siebendũrgen and the Mojave Desert.
Probably most blue chalcedony is dyed. It is wrongly called sapphire,
and there is danger of confusing it with the rare gem mineral of the
same name. See BLUE MOONSTONE.
blue earth -
The name given to the gray-green sand bed in East Prussia
near the shores of the Baltic in which amber occurs. The bed is between
12 and 18 feet thick and is mined at Palmnicken, where it lies about 140
feet below surface. It only outcrops below sea level and storm
waves wash out the light amber and cast it on the shore.
blue gold -
An alloy of light blue color usually composed of iron and
blue ground -
The fresh rock of the diamond pipes, in which the diamonds
occur. See KIMBERLITE.
blue jasper -
A dyed fine-grained quartz rock sold under the name of
blue John -
A banded variety of fluorite, used in carved art objects,
coming from Derbyshire, England.
blue moonstone -
Name given to blue chalcedony.
blue onyx -
Dyed chalcedony. See ONYX.
blue pearl - 1.
Naturally bluish-tinted pearl, usually cultured, which is
discolored by mud inclusions under the nacre. 2. The dark-hued
Pinna pearl, from La Paz and Panama.
Acid used for whitening steel after color-tempering.
Hydrochloric acid, or a mixture of equal parts of sulphuric and
hydrochloric acids, is mostly used.
blue spar -
blue Wesselton -
An early color grade for diamonds, between River and
Wesselton; sometimes called Top Wesselton.
blue white -
Term to describe the color of a diamond. It includes
anything from a Jager to a Silver Cape, since bluish glints in dispersed
light tend to counterbalance the body color of all grades except Capes
and Yellows. By Federal Trade Commission rule, it is an unfair trade
pratice to use the term blue white, or any other term,
expression, or representation of similar import as desciptive of any
diamond which under normal, north daylight or its equivalent, shows any
color or any trace of any color other than blue or bluish. Better
Business Bureaus recommend avoidance of the term, and the American Gem
Society prohibits its use.
A name sometimes given to Water-of-Ayr stone, used as a lap
for flattening brass, gold, etc., made into watch or clock parts, prior
to polishing or other finishing operations. This term should not
be confused with bluestone meaning sulphate of copper or blue
bluing - One of the colors resulting from slowly heating hardened
steel. The colors form yellow, brown, purple, and finally blue.
Besides bluing steel for tempering its working qualities, it is also
done to obtain a pleasing color on watch parts, screws, springs, hands,
bluing pan -
A shallow flat pan in which polished steel parts are placed
for bluing by heat.
blunt hexagonal barrel brilliant -
A type of stone
cutting employed for beads.
blunt hexagonal barrel faceted -
A type of stone
cutting employed for beads.
Local Nevada name for a naturally shattered and recommended
green and red jasper.
Sand bobbing is a process used for polishing soft metals
and removing scratches, pit marks and other imperfections without
dragging the metal.
bobbing compound -
A tripoli type compound used as a fine abrasive before
- (Bob-row’ka) Demantoid garnet, from the name of a brook in
the Urals along which they were found in gold panning operations.
bocco de fogo -
Brazillian name for tourmaline with a pink center and a
green margin, commonly known as watermelon tourline.
Bohemian chrysolite -
Bohemian garnet -
Dark red pyrope garnet.
Copper or ceramic-lined pan to boil acid in finishing
parts or dissolving broken-off screws in watch plates.
boke - Japanese name for pale rose-colored coral.
Boley gauge -
A Vernier slide gauge of light construction convenient for
use by watchmakers and jewelers.
meaning: To cut a stone for maximum diameter, regardless of ideal
proportions; derived from Asian practice of “spreading.”
Bombay pearl -
Arabian or Red Sea pearl, commonly marketed through Bombay.
The convex surface related to watch jewels or dials.
(boe’na-mite) Misleading trade name once applied by one
firm to the blue-green smithsonite from Magdalena, N.M.
bone turquoise -
A substitute for turquoise, composed of bone, teeth or
ivory, naturally, or artificilay tinted blue. See ODONTOLITE.
bony amber -
A variety of opaque amber resembling ivory or bone, white
to brown in color, and somewhat softer than other ambers. See
BASTARD AMBER, SEMI-BASTARD AMBER.
Term used to define the boot-shaped part of the watch regulator in
which the hairspring’s active length can be adjusted.
boracic acid -
(Or boric acid).
An acid in crystal form used as an anti-oxidizer. See
borax - 1.
A chemical substance used as a flux in soldering precious
and other metals. Borax of lump form rubbed with water on a slate, or as
crystals powdered and dissolved in water, is applied to the joint and
the pieces of solder thereon, before heat is applied to melt the solder.
2. A slang term used to denote unethical merchandising practices,
such as selling inferior goods at inflated prices, and making
exaggerated claims and statements in advertising or selling.
boring chuck -
A drill chuck.
Bornholm diamonds -
Misnomer for quartz crystals from marl concretions at
Laesaa and Olanaa, Denmark.
borosilicate glass -
(boe”roe-sill’i-kate) A sodium, boron, silica glass used
in imitation gems. The refractive index is ca. 1.50, the gravity 2.36.
An old French word meaning bastard and applied variably to low quality
diamonds, either the poorest quality, usable only for cutting purposes
(Africa) or to all diamonds of non-gem quality. Also spelled boart,
boort, bortz, and bowr. See BALLAS, CAPBONADO, BLACK DIAMOND.
boss - 1.
A protuberant ornament. 2. A swage or die for
shaping metals. 3. Raised part of a watch bridge such as for a
crown wheel bearing or upon which the regulator racquet is seated.
Boston caliber -
Term used by the Swiss to define their imitations of the
18-size American watch movement and upon which they placed names of
American communities. Later outlawed by U.S.
bottle stone -
bottom corner facets -
The large four-sided facets which alternate with the
pavilion facets on the pavilion of a brilliant. See PAVILION FACTS.
bottom plate -
Main plate of a watch movement.
boulder opal -
Brown iron oxide nodules containing opal-filled fissures,
found in the opal beds of Queensland, Australia.
French term to describe the fused mass from a Vermeuil
furnace. The earliest products were ball-shaped, whence the name, but
now they are greatly elongated and even the German term birne
(pear) is inappropriate.
Bourguignon pearls -
(boor-gee-nyawn’) Earliest imitation pearls of wax-filled
glass beads coated with a “pearl essence” made from fish scales.
Bourse - diamond-trading markets where members
buy and sell good.
bow - 1.The ring or hoop on pendent of a watch case, to fasten
swivel of watch chain to. 2. A curved length of metal or
whalebone, with cord stretched between its ends, for use in driving
pulley in a bow-lathe.
bow lathe -
Small lathe using a bow and string to turn the work to be
Bow-tie Effect - area of less brilliance that appears like a
bowtie; occurs in certain fancy-shape diamonds when the stone's
proportions are poor.
bow-opening pliers -
Long nosed pliers whose ends open when lower arms
are squeezed, to spread open watch pendant bows.
A variety of
serpentine resembling nephrite and often confused with it. It is
tangiwai by the New Zealand Natives and sang-i-yeshen by
box, annealing -
A closed receptacle for annealing steel, packed with sand
or metal filing to exclude oxidization during heating.
box chuck -
Lathe collet with large hollow cylindrical extension in
which are a large number of setscrews to hold object to be turned
box compass -
Compass housed as a marine chronometer. See BOX
box setting -
A setting for a stone in a ring, the top edges of the “box”
being burnished over edges of stones to hold stone setting.
Fine-grained hard wood, from the slow-growing true boxwood
bush - used for laps for polishing steel because it has so close a grain
and is free from gritty matter. Its sawdust was for dying watch parts
and jewelry, after cleaning.
The extension of a mainspring in a self-winding watch,
designed to provide traction against the barrel wall, but to slip when
almost fully wound.
A circular ornament for the arm, of ancient origin;
frequently set with jewels. Bracelets of gold, dating earlier them 3000
B.C., have been recovered from Egyptian tombs.
bracelet watch -
A watch worn on a band or bracelet on the arm -
particularly a wristwatch.
bracelet clock -
Usually a clock requiring a bracket but with a carrying
handle on top. Most often today without the bracket.
brake lever plate -
Lever or plate in which used to stop the balance.
bras en l’air -
An old sector watches with human figure whose arms are
raised to indicate correct time when the pendant is depressed.
An alloy metal composed of various proportions of copper
and zinc-an average formula is 65 parts copper and 35 parts zinc.
To solder or weld with brass; a form of hard soldering.
Brazilian chysolite -
Chrysoberyl. See CHRYSOLITE.
Brazilian diamond -
Often a misnomer for rock crystal quartz. Many true
diamonds are found in Brazil, so it is very confusing misuse.
Brazilian emerald -
Misnomer for green tourmanline, abundant in Brazil.
Especially bad since true emeralds are known from Brazil. See BAHIA
Brazilian pebble -
Brazilian peridot -
Misnomer for light-colored green tourmaline. See TODO MUNDO.
Brazilian ruby -
Misnomer for a red or pink topaz, developed by heat
treatment of a normal brown stone.
Brazilian sapphire -
Misnomer for blue tourmaline, or, more rarely, light
blue to white topaz.
A hydrous sodium aluminum phosphate occurring in a
pegmatite in Minas Gerias, Brazil, in large yellow green monoclinic
crystals and subsequently discovered in New England dikes. It has been
cut into clear yellow greenish gems, with a refractive index of about
1.60; H.5½: S.G. 3.03. Recognized as a new mineral and named in 1944 by
Dr. Frederick H. Pough.
Uniting metal parts by heating them red-hot and using brass
solder - also called hard soldering.
Arch above clock cases interrupted in center by a cut or a
continuation in scroll work on each side.
break facets -
See GIRDLE FACETS.
breast pin -
A pin or brooch worn at the V of a dress.
- (brech’i-a) Geoliogical term for a naturally re-cemented
rock composed of angular fragments. Many decorative stones show this
Breguet compensation -
Bimetallic extension to the regulator acting on the
Breguet hairspring -
A hairspring whose outermost coil is raised and
curved inward to effect isochronisms.
Brequet hands -
Moon or crescent hands.
Brequet key -
Winding key with a slanted ratchet clutch to prevent
winding except in one direction.
Breguet stopwatch -
Two small toothed wheels on the mainspring barrel, one of
which has a blank tooth to limit the winding and unwinding of that
Briacon diamond -
Misnomer for quartz.
A part of the
framework of a watch movement, fastened to its base by a screw at each
end of the bridge, and containing one or more pivot bearing. See COCK.
bright cut - 1.
decoration on a surface, e.g., a spoon handle. 2. The final
smooth cutting of the metal surrounding a bead set stone.
bright dip -
An acid solution
in which copper or copper alloy articles are immersed to achieve a
bright finish -
The finish that
imparts to silver or gold wares a highly polished mirror-like surface.
bright plating - A process
in electroplating whereby the composition of the solution is such that
it deposits plating that has a polished appearance, requiring no
Brighton diamond -
Brighton emerald -
Misnomer for green bottle glass.
Trade name for
synthetic, rutile structured titania.
When used in
reference to a gem, it refers to the brightness of the stone, which is
related to the surface polish and the internal reflection of light from
the back facets. The ability of a stone to take a polish and the amount
the penetrating light bent (the index of refraction) and eventually
reflected out of the front again, from correctly placed facets, and the
transparency, determine the brilliance of stone.
A type of
cutting, used especially on diamond with 58 facets, and also, now, used
as a synonym for a brilliant-cut diamond. There are 32 facets, plus the
table, above the girdle, and 24, plus the culet, below. See STAR FACETS,
BEZEL, TOP CORNER FACETS, TOP MAIN FACETS, TOP HALF FACETS, BREAK
FACETS, PAVILION FACETS, QUOIN FACETS, SKEW FACETS, SKILL FACETS,
AMERICAN CUT, EUROPEAN CUT; SCAN D.N. STANDARD CUT.
process of putting the final 41 facets on a brilliant cut diamond,
following blocking. See BLOCKING.
Brinell hardness -
An index number expressing a specific degree of hardness of a
substance, found by testing with an instrument that measures the depth
of penetration of the substance by a hard steel ball or point
Pear-shaped stone, bounded by crossing bands of small triangular facets,
used as a pendant.
Bristol diamond -
for quartz rock crystal.
That property of
a substance that causes it to break readily. Tool steel, when hardened,
is extremely brittle. It must be softened or tempered to the degree of
hardness required for its use. Precious metals, when contaminated with
foreign substances or when improperly refined, are usually too brittle
to be worked without breaking.
broach - 1.
A tool used for
enlarging or finishing holes. A cutting broach has faces on
it lengthwise, forming cutting edges - from two to eight of them.
It is slightly tapered. A polishing broach has no cutting
edges but the round surface is slightly scored lengthwise, like the
surface of a burnishing file. See REAMER. 2. Jewelry. See
bronze - 1.
alloy of copper and tin. 2. An artistic production in
bronze, as a statue or statuette. 3. Brazilian term for greenish
diamonds in which the color is in a thin outer skin.
A variety of pyroxene
with a bony hiller color, sometimes used as a decorative stone. See
(broach or brooch) - A
piece of jewelry to be worn pinned to clothing, as at the beck or
shoulder, or the breast or hat, or in the hair.
brooch watch -
Watch that can be
worn as a brooch.
A dark-colored form
of titanium oxide rarely cut as a gem for collectors.
brown hyacinth -
brush, brass, glass.
whose bristles are made of glass or brass fibers used as an abrasive.
bubble - 1.
Gemstones. An apparent void; often they are included crystals of
some foreign substance, but so colorless and so different in refractive
index that they resemble cavities. 2. Glass. Bubbles occur
in the blowing of glass; are one of the best signs that a glass in
handmade; a bubble does not weaken glass.
The crimping of metal under stress.
buff - 1.
A tool for
polishing watch parts after cleaning, a hand-buff of chamois leather or
felt glued to a wooden handle and charged with powdered rouge. 2.
A compact piece of felt or quilted cloth or leather, used with
abrasive materials. Buffs are both of circular form for use in
lathes, and of flat form with handle for use by hand.
buff top -
A low cabochon type
of cutting, the top just slightly rounded, with a faceted pavilion.
bulb opal -
bullet cut -
gem-stone like a baguette except that one end is pointed.
bull’s eye -
(bull’yon) Gold or
silver bar, ingot or other form, as distinguished from coin.
bunch rings -
produced in quantity to sell at popular prices with small center stones.
They were formerly sold in bunches held together with string - hence the
Bunsen flame -
A blue, smokeless
flame from a Bunsen burner, which mixes gas and air, used for various
heating purpose in horology, and jewelry work. Named for the inventor,
a Heidelberg, Germany, chemistry professor, R. W. Bunsen, 1811-1899.
- (beu’rin) An
instrument of tempered steel, used for engraving on metal. It is
prismatic in form, having one end attached to a wooden handle and the
other end ground off obliquely, so as to produce a sharp point.
Burma ruby -
Name given to the
best quality rubies, most of which comes from Burma.
burmite - Amber from Burma,
essentially identical with Prussian amber. Found in dark brown, dirty
brown, or rarely red and light yellow water-worn masses up to skull
sizes. It is mostly sold in the Orient, though much “Chinese
amber” is pressed German amber or bakelite. See CHINESE AMBER.
burnishing - 1.
To produce a polished surface on metal by rubbing it with a
hard, smooth, highly polished steel burnishing tool or agate; this does
not remove any of the metals. Object of burnishing are to brighten,
harden and preserve the metal. 2. To press or swage a
metal corner over the edge of a stone, etc., to hold it in a setting.
burnisher - 1.
A tool for
polishing metal by burnishing. In watch-work, burnishers are flat slips
of smooth-surfaced hard steel, used for polishing pivots, etc.
Burnishing files have one side smooth-surfaced, for polishing
jewel-setting tops, filed pins, etc. 2. A tool for
pressing or swaging metal over the edge of a stone, etc., to hold it in
burnout furnace - A gas or
electrically powered furnace used to eliminate, by burning out, the wax
from investment molds.
burnt - 1.
When applied to a
stone it means that the color has been changed by heating. Amethyst is
so changed to citrine, brown zircons aquamarine, and muddy pink beryl
often changes to fine pink morganite. Many stones are so treated.
2. Steel which has been overheated (hotter then “cherry red”) in
hardening it. Burnt steel has a course grain, is brittle, and will
not take a fine polish.
burr - 1.
On a pivot, a
“head” formed on the end of a balance pivot by a violent thrust against
a cap jewel, due to a fall or blow suffered by the watch. 2.
A milling cutter for forming a seat for a stone in setting a piece of
jewelry, for removal of metal in hard-to-reach areas and cutting special
Repairing a worn
pivot hole in a metal bearing; essentially, lining the hole, after
enlarging it for the purpose, with new metal in which a hole is drilled
to fit the pivot correctly.
butt joint - A joint made by
bringing two metal ends together and soldering or welding them on the
flat without fold or overlap.
butt welding - Welding ends of
metal, as in the ends of a ring shank. Forms a solder less joint.
See BUTT JOINT.
butterfly jewelry - Inexpensive jewelry made from a fragment of a butterfly wing, usually
blue Brazilian Morpho butterfly, covered with glass.
butting - A fault in the
action of gearing in a train, in which the two wheels are too far apart
or the teeth poorly formed, so that the transmission of power takes
place too near the points of the teeth.
button onyx -
Or button opal, is the name given to an opal-agate from New
Mexico in which the common opal alternates in bands with a black
button pearl - A pearl which is
flattened on one side.
Buxton diamond -
Misnomer for quartz, rock crystal.
byon - Burnese name for the alluvial gravels in which
bywater, byewater - An early
color-grading term applied to diamonds tinged with yellow. Same as