No, that measures volume, not gold content. Anything at least as dense as gold, maybe with with gaps in it to match the density, and a layer of gold around it i

No, that measures volume, not gold content. Anything at least as dense as gold, maybe with with gaps in it to match the density, and a layer of gold around it is indistinguishable from pure gold this way. A more reliable and still relatively cheap test is via conductivity.