Billon (alloy)

Billon (/ˈbɪlən/) is an alloy of a precious metal (most commonly silver, but also gold) with a majority base metal content (such as copper). It is used chiefly for making coins, medals, and token coins. The word comes from the French bille, which means 'log'. The use of billon coins dates from ancient Greece and continued through the Middle Ages. During the sixth and fifth centuries BC, some cities on Lesbos used coins made of 60% copper and 40% silver. In both ancient times and the Middle Ages, leaner mixtures were adopted, with less than 2% silver content. Billon coins are perhaps best known from the Roman Empire, where progressive debasements of the Roman denarius and the Roman provincial tetradrachm in the third century AD led to declining silver and increasing bronze content in these denominations of coins. Eventually, by the third quarter of the third century AD, these coins were almost entirely bronze, with only a thin coating or even a wash of silver. Billon coins were frequently issued in varying finenesses up to about 37% silver for fractional denominations in eighteenth-century German states. An example of a United States coin considered to be billon is the Jefferson nickel issued from 1942 through 1945.