Coin silver was once a common alloy in the United States. It is now relatively rare and the name causes some confusion. The technical “coin silver” alloy is .900 prata, ou 90% prata e 10% cobre. It was not used to make coins, but at one point in time it was made from refined scrap coins. Monetary coins in our country, and most others, no longer contain silver and are made from more inexpensive and durable base metals. Coin silver jewelry that is still on the market will bear a quality stamp of .900, and they are rare antiques.