Message:

<p>[QUOTE=&quot;Just Carl, post: 359204, member: 4552&quot;]Most metals combine with the Oxygen in the air and create a new compound. With many coins, such as pennies (cents) the darkening of the coin is usually due to the Copper combining with Oxygen to form Cu20. Originally the cent was a combination of metals of Copper, Zinc, Tin. In addition to the Copper Oxydizing, some of the Zinc and Tin also Oxidize. This new compound being formed of those metals and the Oxygen will slowly change the coin from the original Brassy, bright color to the darkening brownish color. </p><p>Some Copper coins also begin to form a greenish patina. This is also due to the combining of moisture and carbon dioxide in the air to form Copper Carbonate.[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in