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.
Product size 3.1" X 1" X 0.7" Inches (78 X 24 X 18mm)
Contains nitric acid and muriatic acid
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:
Black acid testing stone that is washed thoroughly with water prior to each test
Gold testing needles with solid gold tips used for comparison with test pieces
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, bright color.
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 creamy color
77% to 90% silver will show a gray color
65% to 75% silver will show a light green color
Click to Learn How to Test Gold and Silver