Rare silver coins tend to be very hot items among collectors. While gold coins are more popular with some collectors, the fact that silver shows its age but doesn’t decay sometimes gives these coins a more obvious connection to history that experienced collectors enjoy. These coins will tone over time, turning a blackish color, but the surface underneath is unaffected. This is not the same sort of reaction with the atmosphere as is rust, where the metal is actually oxidized in the process. Toning simply creates a layer of black that may obscure the coin. In some cases, it actually enhances the details.
Rare silver coins have to be certified before you’ll be able to sell them to a dealer. This involves sending it to any of the major numismatic societies and having one of their experts look at the coin. If you know a bit about coinage, it’s likely that you’re going to be very excited to have this done. The numismatist will, first and foremost, authenticate the coin. This is done using their extensive knowledge of history, of coin designs, of metallurgy and using an array of instruments that allow close, but non-destructive, examination of the coin in question.
Rare silver coins that turn out to be genuine will then be graded. This process involves assigning an alphanumeric designation to the coin that describes its general condition. This grade can range from essentially pristine to something that is certainly a coin, but about which little can be determined beyond that fact. Most coins will fall somewhere in between. A coin that was used as currency will likely have a lot of nicks and scratches; a coin that was kept by a collector may look as if it was minted just a day or two before you saw it.
If you want to sell rare silver coins, be sure to go through a reputable dealer. Don’t be afraid to hunt around for a good deal. These coins can be tremendously valuable and, over time, they tend to increase in value as stocks become even scarcer. The most important things that you can do are to store the coin safely, never remove it from the slab that contains the certification information and never clean the coin. The toning is considered an asset by some collectors. Cleaning the coin will render it next to worthless, and destroy an historical object.