Professional jewelers and jewelry often use gold acid tests to determine gold jewelry’s value. Different acids react differently when dripped on gold. Testing for gold with acid focuses around the fact that gold is a noble metal which is resistant to change by corrosion, oxidation or acid. The acid test for gold is to rub the gold-color item on black stone, which will leave an easily visible mark. The mark is tested by nitric acid, which dissolves the mark of any item that is not gold. If the mark remains, it is tested by applying nitric acid and hydrochloric acid. If the mark is removed, then this test dissolved the gold, proving the item to be genuine gold.
Gold is not a hard metal so there are a number of hardness tests that can be done, although these can result in a partial destruction of the real gold item:.
- A sharp pin should dent a real gold item but will break if the metal is harder than gold.
- The same theory also applies to a bite test, a bite should mark the gold.
- Try scratching glass with the piece of gold. If it scratches the glass, it is definitely not gold, or is mixed with other metals and the purity is very low.
High gold his quality is more yellower. To seek strong ornament and colour desired, pure gold should mixed with other metals. Metals common use for mixture gold ornaments is Copper,Silver, Tin and Nikel. Beside raise different gold strength then metal mixture also to seek colour desired
- Emas Merah – Gold MixWith Copper.
- Emas Kuning – Gold Mix With Silver.
- Emas Putih – Gold Mix With Tin and Nikel.