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<p>[QUOTE=&quot;The Eidolon, post: 8310559, member: 102103&quot;]Well, I tried testing out my idea of calculating composition from volume and weight.</p><p>It didn&#039;t really work.&nbsp; For a zinc penny I calculated a volume of 0.421 cc and weight of 2.49 g for a density of 5.9 g/cc.&nbsp; Zinc has a density of 7.13 and copper of 8.92.&nbsp; The weight is fine (2.50 g on <a href="https://en.numista.com/catalogue/pieces10969.html" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://en.numista.com/catalogue/pieces10969.html" rel="nofollow">Numista</a>) so the volume must not be accurate enough.</p><p><br /></p><p>Any density measurement outside the range of the two constituent metals is a garbage result and can&#039;t be used to estimate composition.&nbsp; Maybe the thickness measurement isn&#039;t accurate enough to be useful due to the relief texture of the coin.&nbsp; Maybe wear throws it off.&nbsp; Anyway, don&#039;t take my advice--specific gravity measurement is much more accurate.&nbsp; You could probably tell the difference between gold and silver or copper by estimating the volume because the difference is so huge, but for any metals close in density like copper and zinc it&#039;s not practical.&nbsp; Oh well.</p><p>[ATTACH=full]1471058[/ATTACH][/QUOTE]</p><p><br /></p>

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