The original Mexican 50 Peso Gold Coin, also known as the Centenario, was first minted in 1921.  It commemorated the 100th anniversary of Mexico's independence from Spain.

The more common 50 Peso coin is a restrike, minted between 1949 and 1972.  The original strikes may trade for a slight premium over the restrike.

It contains slightly over an ounce of gold (1.2057 ounces), and is mixed with 10% copper to give a karat of 21.6.