Use these test needles to compare acid reactions with gold items to be tested. Choose a karat needle, rub or scratch the needle against a test stone, and make a rubbing or scratch with the item to be tested next to it. Place a drop of testing acid across both marks, and carefully observe the reaction to the acid.

How do you test gold content?

The Nitric Acid Test

Gold is a noble metal which means its resistant to corrosion, oxidation and acid. To perform this test, rub your gold on a black stone to leave a visible mark. Then apply nitric acid to the mark. The acid will dissolve any base metals that aren't real gold.

How can we check purity of gold at home?

To convert karats into the per centage, you need to divide the karat number by 24 and multiply the result by 100. So, for example, to find out the gold per centage in your 22 karat ring, divide 22 by 24, the result is 0.9166, multiply it with 100, so it equals to 91.66 per cent - that's the purity of your gold.