US Silver Coin Bag

These

Pre-1965 legal tender ninety percent silver coin bags

 (dimes and quarters) are traded based on silver weight.

$100 face value bags contain silver content of 71.5 troy ounces. The coins are ninety percent silver and ten percent copper.

In 1965, by order of Congress, the US Mint removed all silver from dimes and quarters. Silver content for half-dollars was reduced to forty percent up until 1972, when all silver was removed from the half-dollar as well.