How to determine what metal medallion is made of?

A. Hi Querube. That's a tall order. If you tell us where you got it and what it appears to be made of (copper, stone, etc.), and about how big it is, it might still be a tall order, but maybe not quite so unlikely :-)

Luck & Regards,

A. You came up with a specific gravity of 54/15, or 3.6. The specific gravity of copper is 8.89, and that of tin and zinc are in the low 7's. So any brass, bronze, or copper alloy should have a specific gravity at least twice what you determined. The specific gravity of aluminum is 2.7, so that'a a possibility if your scale read high. Considering the presumably yellow color and the green discoloration, however, aluminum doesn't sound likely. I'd say a good experiment might be to use a chunk of material of known or knowable specific gravity and volume to calibrate your experiment. You'd need a much much more accurate specific gravity in order to use it as a piece of the puzzle. There are many chemical "spot tests" to help determine materials, but they tend to be destructive tests.

A. Density might not work since a number of medallions of the type mentioned were stamped out or cast in two pieces and then joined, i.e., slightly hollow. A second possibility is that it was cast out of aluminum and plated quite heavily with copper and then a brass top coat or a very low alloy gold.