Gold mining or test at home

Note any discolorations on your skin from wearing or holding the gold. Pure gold doesn’t react with sweat or oil from your skin, so if you see black or green marks, they are from other metals. Silver leaves behind black marks and copper leaves behind green marks. If you see a lot of these marks on your skin, your gold may be less pure than you expect.[4]

Keep in mind that most gold items are blends of gold and other metals. Even something like a 14K piece of jewelry, 58.3% gold, can leave these marks. Use other tests as well to ensure your gold is authentic.