What is Billon

Billon is a silver-colored alloy containing a precious metal, usually silver or mercury, along with a base metal like copper ^{[1, 2]}. Its name is derived from the French word ‘bille’ that means ‘log’ ^[2]. It was a popular metal alloy used during the ancient times and throughout the Middle Ages in Greece and Rome ^{[2, 3]}.

Composition

Silver/Mercury	Less than 50% [1, 2]
Copper	More than 50% [2]

Use

It is commonly used for producing medals, coins, and token coins ^[2].

Interesting Facts

• Some cities on the Lesbos Island in Greece used coins containing 40% silver and 60% copper during the 6th and 5th centuries BC ^[2].
• Scottish bawbee coins were made from billon and were used during the reign of James V ^[2].
• The Romans used antoninianus, a billon coin introduced by Emperor Caracalla in 215 AD, was made of bronze and a minimum amount of silver ^[2].
• A Japanese billon named shakudo (containing 4-10 percent gold and 96-90 percent copper) can be used to produce indigo or black patina ^[4].