Reverse: The design used was based on the 1921 gold Centenario, a coin issued to mark the centennial of Mexican independence. The winged Victoria of Angel of Independence is in front with the volcanoes Popocatépetl and Iztaccihuatl in the background. The weight ( or ounce), date, and purity are also listed. The older Libertad coins show a front-facing view of the angel. The new Libertad series shows a three-quarter side profile of the angel. The gold used the older angel from 1981 through 1999. The silver used the older angel from 1982 through 1995.