Hobbies And Interests
Silver Quality
Sterling silver contains 92.5 percent silver, with the remaining 7.5 percent made up of other metals, typically copper. A higher grade than sterling silver is fine silver, which contains 99.9 percent silver. American-made sterling silver are sometimes stamped with the demarcation "925" to indicate the silver percentage; some countries, in fact, require sterling silver to contain this marking as a guarantee of authenticity. Other markings such as "Mexican Silver" or "German Silver" don't guarantee silver content, and may not be sterling silver.
Testing Silver
The most effective way to determine the purity of silver is to test it. Several types of precious metal test kits are available for testing silver, gold and other metals. The process entails rubbing the metal onto a testing stone and then applying an acid to the stone. There are different acids used to identify the purity of different metals. In order to test silver, pure nitric acid is used. Silver that is 99.9 percent pure will turn bright red. Silver that is 80 percent silver will turn brown, while a piece that is only 50 percent silver will turn green.
18kt Acid
When testing gold, test acids are available to test 10kt, 14kt, 18kt and 22kt gold. If you believe a piece is 18kt gold, then place a drop of 18kt acid on the metal. If the acid dissolves the metal, then the piece is not 18kt gold and contains a lesser carat level. If the metal does not dissolve, then it is the same carat level as the acid you're using to test it. Acids for testing gold, however, are not the same as those used to test silver. If you place 18kt testing acid on sterling silver, the silver will turn a grayish white color.
Pure Silver
The only other way silver could become white, other than coating the silver with white paint, is if it's pure silver. Pure silver, unlike sterling silver, is almost perfectly white. Pure silver, however, is rarely used to make jewelry or other objects, as it is too soft for general use and is malleable to the touch. The small amount of copper added to sterling silver serves to harden the silver. Although it's highly unlikely that anything would be made from pure silver, it would appear white. Sterling silver will only turn white, however, from the application of 18kt test acid.