I'm curious about some coins I've seen (I don't have any recently to show on the post), but it is occasionally I've seen coins that have a coloration on them. It almost looks like the metal was over-heated. Is this caused a the mint? Is it classified as an 'error coin'? Thanks for your time and input.
Most is what is called toning, involving chemical reaction after it has left the mint, either natural ( environmental) or artificially applied. This would be post mint, no error or variety . Some such as red spots on gold or 'milkspots' on silver are considered to be caused by the mint by some, others believe it is caused after they leave the mint. jim
I think you mean coin toning, which is a phenomenon where the coin metal changes color. This can occur naturally or artificially, and can be worth alot of money if natural. These things happen when the metal reacts with chemicals, such as when silver reacts with sulfur, it creates silver sulfide (which is the color that you see). Most of the time it gives a very pretty color, which can either be rainbow, blueberry, lime green, anything. However there is artificial toning, which definitely doesn't look as nice as a natural toned coin. Artificial toning is like cleaning a coin, though it is used to decept buyers into thinking they are buying a naturally toned coin when really it is just a doctored coin. I hope I answered correctly. The mint doesn't create toning, so no it wouldn't be considered an error coins. Natural toning can give a $50 coin a very high premium.
This is what some jewery makers use to color there metals. As we know people are color orientated.It helps the product sell. lots of youtube vids.https://www.sciencecompany.com/Patina-Chemicals-Patina-Book-C672.aspx?s=Name ASC&p=1 Patina on a coin can show that it has not been cleaned/dipped. It takes a long time for this to develope naturaly which can give it an added premiun. It is called Tannish if it is not wanted, and Patina if it is wanted. it's all a type of oxidiation, Google Rainbow Toning and click Images.
