Using the corresponding test acid, our
selection of 10k, 14k, 18k, 22k, silver, and platinum test acid will help
jewelry buyers and sellers to accurately determine the karat value of their gold
and to determine the purity of silver. Supplied in sturdy plastic bottles
maximizes safety and allow the user to easily squeeze out a drop at a time.
Procedures for testing
Gold, Platinum, and Silver
To test for the karat value of
gold, platinum, and silver, you will need the following materials and tools:
Separate tests are applied for
each type of metal, as identified and described below.
To Test For 10k, 12, 14k
Scratch the gold piece to be
tested on the stone. Next to this position, scratch the appropriate needle (10,
12, or 14k). Place a drop of the appropriate acid on the stone where the gold
was rubbed off. If the gold is the same karat or higher, the color of the
scratch mark for the gold piece will appear the same as the mark from the
needle. If that gold piece is a lower karat, the scratched deposit will become
fainter and eventually disappear.
To Test For 18k
Scratch the test piece on the
stone and apply 18k acid. Any gold that is less that 18k will disappear in less
than 30 seconds. Gold that remains on the stone is 18k or higher.
To Test For Platinum
Scratch the test item on the stone
and apply platinum acid. If the material is platinum, it should keep its white,
The same procedure can be used for
18k white gold. The material on the stone should start changing to a light
bronze color in about 3 minutes.
For 14k white gold, the material
on the stone should disappear in 15 seconds.
To Test For Silver
Place a drop of acid on the object
to be tested.
90% to 100% silver will show a
77% to 90% silver will show a gray
65% to 75% silver will show a light
Click to Learn
to Test Gold and Silver