structural:expansion, structural:summarization
Silver coins are one of the oldest mass-produced form of coinage. Silver has been used as a coinage metal since the times of the Greeks; their silver drachmas were popular trade coins. The ancient Persians used silver coins between 612–330 BC. Before 1797, British pennies were made of silver. As with all collectible coins, many factors determine the value of a silver coin, such as its rarity, demand, condition and the number originally minted. Ancient silver coins coveted by collectors include the Denarius and Miliarense, while more recent collectible silver coins include the Morgan Dollar and the Spanish Milled Dollar. Other than collector's silver coins, silver bullion coins are popular among people who desire a "hedge" against currency inflation or store of value. Silver has an international currency symbol of XAG under ISO 4217.