Jewelry tester evaluation set, changes color according to, very easy to use. Apply a drop of this solution to a small sample of the item to be tested onto the test stone. Jewelry tester, apply test on the stone, real will stay on the stone, fake dissolved or oxidized blue. This gold jewelry testing tool is used to check the gold content of items, works to test what you think is 10k, 14k, 18k, 22- and pure. Test stone, practical jewelry making accessory, ideal for testing jewelry, coins, antique, silver, collectibles, etc.