GOLD TESTING PROCEDURES
No precious metal is magnetic.
We use 10k, 14k, 18k, 22k nitric acid on a scratch test.
If the scratch stays the same color, no change, as the acid used, it is that karat of gold.
If the scratch turns brownish, it's a lessor karat than the acid used to test it.
If the scratch disappears, it is not gold.
In some cases, especially heavy items, we will file into the item and put acid directly on the item.
If the acid stays clear, it's good. If it turns bubble green or blue, it is plated.
Silver Testing: 18k acid will turn the silver scratch into a bright blue color