text: The Napoléon is the colloquial term for a former French gold coin. The coins were minted (at various times) in denominations of 5, 10, 20, 40, 50, and 100 francs. This article focuses on the 20 franc coins issued during the reign of Napoléon Bonaparte, which are 21 mm in diameter, weigh 6.45 grams (gross weight) and, at 90% pure, contain  of pure gold. The coin was issued during the reign of Napoleon I and features his portrait on the obverse. The denomination (known as the Franc Germinal) continued in use through the 19th century and later French gold coins in the same denomination were generally referred to as "Napoléons". Earlier French gold coins are referred to as Louis (the name of eighteen French kings) or écu (an old French word for shield). Gold Napoléons have historically proven more resilient than other gold coins to economic forces, such as after the Suez crisis when unlike other coins Napoléons did not weaken.
  Overview
  The coins were originally minted in two denominations, 20 and 40 francs for Napoléon Bonaparte. The 40-franc gold piece did not become popular. The 20 franc coins are 21 mm in diameter (about the size of a U.S. five-cent piece or a Swiss 20 Rappen coin), weigh 6.45 grams (gross weight) and; at 90% pure, contain  of pure gold. The 40 franc coins are 26 mm in diameter, weigh 12.90 grams (gross weight) and; are 90% pure gold.