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Author: Admin | 2025-04-28
Are you interested in learning how to authenticate and determine the purity of gold and silver jewelry? Look no further! In this tutorial, we'll show you how to test gold using a touchstone and acid solutions. Testing gold and silver jewelry using a touchstone and acids is a common method used by jewelers to determine the karat of gold jewelry. It's a simple yet effective method commonly used by jewelry buyers, sellers, and collectors. By the end of this tutorial, you'll have the knowledge and skills to confidently test gold and make informed decisions when buying or selling scrap gold jewelry. So let's get started!This method involves making a scratch on a touchstone, a black stone with a smooth surface, with the jewelry being tested and then applying a drop of a gold testing acid to the scratch. The reaction of the acid with the gold will depend on the karat of the gold, and by comparing the reaction to known standards, the karat of the gold can be determined.The gold testing acids should include solutions for 10K, 14K, and 18K gold, as well as a solution for testing silver. It is also helpful to have a solution for 22K gold, but this is not necessary.You can also make the gold and silver acid test solutions yourself quite easily, by mixing the following amounts of reagents:10K acid: 22.2 mL nitric acid and 7.4 mL distilled water14K acid: 23.7 mL nitric acid, 5.9 mL distilled water, and 10 drops hydrochloric acid18K acid: 5.9 mL nitric acid, 5.9 mL distilled water, and 17.8 mL hydrochloric acidSilver acid: 20 grams potassium dichromate, 22.2 mL nitric acid, and 7.4 mL distilled waterTo test the karat of gold jewelry using a touchstone and acids, follow these steps:Scratch the gold jewelry being tested over the surface of the touchstone, pressing hard to leave a visible deposit. It is best to leave a line of about one inch long.For the highest sensitivity, place a scratch line with a gold test needle next to the scratch line of the jewelry being tested. Compare the speed at which the scratches dissolve. If the test scratch dissolves faster than the needle scratch, it is a lower karat than the needle.Place a drop of the 10K acid on the scratch made by the jewelry being tested. If the acid dissolves the scratch, the jewelry is less than 10K gold or not
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