One test for silver is whether it has black spots on it. Almost a guaranteed sure sign that it is silver. But I am confused as to why sterling does not tarnish as fast as coin silver or silver of less than
92% pure. Reason would say that the higher the silver content the faster it will tarnish to black. Unless my observation is incorrect for I seem to notice that sterling tarnishes more slowly than does less pure silver.Archimedes Plutonium