Mexico is known for producing some of the largest silver coins in the world, which is highlighted by the Libertad. The coins are struck in pure 99.9% fine silver and are available in a variety of sizes, although they were initially launched in just 1 oz. That changed in 1991 when coins of 1/2 oz, 1/4 oz, 1/10 oz, and 1/20 oz sizes were added. 2 oz and 5 oz size was added in 1996. The latest addition was 1 kilogram size in 2002.
The obverse or heads side of the coin features an eagle battling a snake (Mexico's national coat of arms),which is surrounded by a wreath and the words "ESTADOS UNIDOS MEXICANOS". Encircling the center are ten eagle designs that have been used as National Emblems through the centuries, including one depicted in the 16th century Mendocino Codex.
The reverse or tails side of the coin features the famed winged angel design. The angel towers above a background of the volcanoes Popocatépetl and Iztaccihuatl.
Inscription surrounding the top include the numerical size following by "ONZA" for "ounce", then "PLATA PURA" for "pure silver", the year of issue, "LEY" and ".999".