Gold Test (Black) Stone - 2x1.5

Premium quality black hard gold testing stone. Use for determining the carat content of jewelry. Jewelers use these dark test stone to test gold karat as well as silver and platinum. The object to be tested is scratched on the surface of the stone and a test acid solution determines the karat of the scratch. Can also be used with test needles to confirm karat markings.
Size: 2x1.5