Thread: How do you tell the difference between gold and brass coins?

I have a Presidential medal. How can I know if it is a gold or brass?
weight test, density, battery acid?
Does gold tarnish after, 61 years?

Gold doesn't tarnish.

Sorry.
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Gold is softer and does not oxidize.

Gold is significantly heavier than brass. so do a density test. My guess is you have a brass metal.

One of the beauties of gold, is that it does not tarnish.

(Put a grain of table salt on the metal. If you see it turn green or the metal is blackish, then you do not have gold.

Gold never tarnishes -- it is a noble metal and its oxidation is energetically unfavourable.
The density of gold is 19.3 g/cc - much higher than that of brass (8.4 g/cc).
Another test that you can carry out is to place it in nitric acid. If it is brass, it will dissolve spectacularly and give off brown NO2 gas (do this in a ventilated area!) If it is pure gold, it will be unaffected, and you can remove it (using something made of plastic, I would hope) and wash it off.