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<p>[QUOTE=&quot;Conder101, post: 137365, member: 66&quot;]The problem with determning brass/copper/bronze composition is that weight and specific gravity tests usually are indeterminate unless it is something like a 60- 70 % copper 30 - 40% zinc&nbsp; alloy.&nbsp; Brass can be any combination of copper and zinc but once the zinc drops to the 5 - 10% level it can have the same color as copper or bronze and can also tone or tarnish to roughly the same color as well.&nbsp; (And most references on foreign coins don&#039;t bother to give the compostion percentages, they just say brass.)&nbsp; And copper, brass, and bronze have almost identical specific gravities.&nbsp; The only REAL way to tell the composition is through the SEM/w-Ray test, or through destructive assay.</p><p><br /></p><p>I run into this problem a lot with Chinese coins.&nbsp; Many issues come in common varieties made of copper, and rare varieties made of &quot;brass&quot;, but with no percantage compositions given.&nbsp; A cleaned copper coin LOOKS like brass, but so does a cleaned brass coin.&nbsp; And without a listed percentage composition, for all I know the description of the brass variety may have been taken from a cleaned copper coin.&nbsp; For that reason I have simply decided that most if not all of the brass varieties probably don&#039;t exist because that can not be definitively identified.[/QUOTE]</p><p><br /></p>

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