How do you tell if a piece of jewellery is really gold or simply base metal with a gold overlay? After reading this article, you will know how to test gold and silver for its purity and where, on your item of jewellery, is the best place to test inconspicuously. Testing gold and silver is an easy task, but it can mess up your jewellery if you test in the wrong place on the item.
Gather the materials needed and cover your work area with newspaper so that no acid is spilt on your counter top or table top. Place your testing stone on the newspaper and place the jewellery out of the way so that no test acid gets splattered on it.
Scratching the test stone with the edge of a ring or necklace link is probably the best area to test these items. The scratch doesn't leave large scars on the surface of the item this way. When scratching the jewellery item on the test stone, make sure you push with a little bit of force in order to leave tiny pieces of the gold or silver on the stone. You will notice there is a streak on the test stone when you have scratched it correctly. After scratching the test stone simply drop one drop of test acid on the streak of metal left on the test stone.
Look for change in colour. If you are testing gold, you are looking for the streak to change only slightly. This is what tells you what carat the gold is. If you are testing with 14k gold acid but the item is not 14k, it will either disappear, indicating it is less that 14K, or it will not change at all, indicating it is higher that 14K. If you are testing silver, you want the streak to change in the following manner: Dark Red = 925 Silver; Brown = 800 Silver and Green = 500 Silver.
Filing a groove in the piece is another method of testing an item of silver. Simply file a groove in an inconspicuous location on the piece. Drop one drop of test acid for silver on the piece and wait for the change. Testing the piece itself is possible with the silver solution but it has a tendency to dull the finish and leave a stain where the acid was place. So this method is not recommended on fine pieces.