Improper Alloy Error

Hi,
It depends on the coin, it depends on whether it is or isn't. Many coins thought to be an improper alloy mix are just discolored coins.

It depends on whether the coin might or might not be struck on a planchet intended for another type of coin.

Or it could be normal. For example, early lincoln cents sometimes have a "wood grain" appearance due to alloys improperly mixed.

So without more of a description or a picture of the coin, and with the possibility that the coin could be identified incorrectly as an Improper Alloy Mix, it is impossible to answer your question as it is.

Thanks,
Bill

There's also the consideration that a coin may merely appear to be an improper alloy such as the stated example of Lincoln cents by FoundInRolls, e.g., freshly oiled dies or planchets will often impart an anomalous coloration.

Further, how would it be determined than an alloy is improper except by taking a specimen from the coin and metallurgically analyzing it thus destroying whatever value it might have?

Fred

I agree that a specific gravity test can tell you if the coin is on a wrong planchet, I'm not so sure about just an improper mix of metals ? I guess it would depend on if the the metals used were incorrect or if just the proportions were off.

what coin are we talking about ?

that would be a good place to start !

I have a 1979-D with the appearence of wood grain. Can't post a picture, something about website can't display page. Oh well I figure it out.

I have a 1930 Lincoln Cent that is improper alloy. "Wood grain" streaks. I will post tonight when I get home from work.

I found this, Split Planchet

http://lincolncentresource.com/Erro...lanchet.html

Sounds just like the one above!

Copper has a high melting point, tin and zinc have much lower ones. If the metal is not kept mixed, or if it cools too much during the pour, or if the ingots cool too slowly alloy will not be homogenous and the metals will start to separate somewhat. This means that when the roll out the ingot some areas will be higher in tin/zinc than other areas. Since the ingot is rolled and stretched out these areas will be in the form of streaks. These areas of high and low tin/zinc content will often tone at different rates. (areas of high tin/zinc content tend to be more resistant to toning) This results in the "woodgrain" pattern we see on the coin. I wouldn't call it a mint error, just sloppy foundry work.