Pure gold, or 24 carat gold, is soft and yellow. Gold quality is measured in carats. For example, 18 carat gold is 75 per cent gold, 14 carat gold is 60 per cent gold, 12 carat gold is 50 per cent gold and 10 carat gold is 40 per cent gold. The best way to determine the quality of gold is to purchase an acid gold test, which contains a black testing stone, scratch test needles and acids for 10, 14 and 18 carat gold.
Scratch the gold item over the black testing stone that comes with the kit. Scratch the stone until a solid line appears.
Create a second scratch with one of the gold scratch needles provided with the kit on the test stone.
Put a drop from the 10 carat gold acid test onto the scratch from the gold material. Put another drop on the scratch from the gold scratch needle for comparison. Watch carefully. If the acid dissolves the scratch from the gold material, it is less than 10 carat gold.
Repeat steps 1 and 2. Then use the 14 carat gold acid to test the scratch. If it dissolves, it is less than 14 carat gold. However, if it dissolves slowly and leaves some colour on the test stone, it is most likely in the 12 carat gold range.
Repeat steps 1 and 2 and use the 18 carat gold acid to test. Once again, if the scratch does not dissolve quickly and some colour is left on the stone, it is probably approximately two carats below the test acid.
Use extreme caution when handling acid. Wear protective clothing and gear and keep away from children.