The international trading partners did not like the fact that U.S. coins were reduced in weight. The use of much more common half dollars became problematic since merchants would have to separate higher value pre-1853 coins from the newer reduced ones. From 1853 onwards, trade with Asia was typically done with Mexican coins that kept their weight and purity in the 19th Century. This ended in 1874 when the price of silver dropped so that a silver dollar has less than $1.00 worth of silver in it (because of huge amounts of silver coming from the Nevada Comstock Lode mines). By 1876, all silver coins were being used as money and by 1878, gold was at par with all U.S. paper dollars. Beginning in 1878, huge amounts of the Morgan silver dollars were produced but few were used as money. The size was too large to carry on business so Silver Certificates were used instead. The mint made the coins, placed them in their vaults and issued the Silver Certificates instead. This is the reason so many Morgan and Peace dollars can be purchased in AU or UNC condition (near perfect)... they sat in bank/U.S. Treasury vaults most of the time.