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 0.1867 troy ounces (5.807 g) 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.