This two-coin set commemorates the 30th anniversary of the silver Libertad range, and has one proof coin (the one ounce, known in Spanish as "onza") and one bullion (Brilliant Uncirculated) coin - the half ounce. Unlike other years, in 2012 only the silver proof ounce had a proof version and the other silver sizes did not, so that the customary annual proof sets were not issued.
The Libertad series of silver and gold bullion coins is issued by Banco de México (the Bank of Mexico) and is minted by La Casa de Moneda de México (the Mexican Mint). The Mexican Mint was established in 1535 and is the oldest mint in the Americas.
The reverse design is based on the 1921 gold Centenario, a coin issued to mark the centennial of Mexican independence. The winged figure of Victoria from the Angel of Independence monument in Mexico City is depicted in front of the volcanoes Popocatépetl and Iztaccihuatl.
The Libertad series is interesting with the fact that the coins do not have a face value, but are accepted as currency and guaranteed by Banco de México based on the market value of their precious metal content. | 
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