Depicts the seal of the United Mexican States.

The Seal of the United Mexican States is a modified version of the national coat of arms, with the addition of the full official name of the country Estados Unidos Mexicanos, in a semi-circular accommodation in the upper part of the seal. Current and past Mexican peso coinage have had the seal engraved on the obverse of all denominations.

The coat of arms depicts a Mexican golden eagle perched on a prickly pear cactus devouring a rattlesnake. To the people of Tenochtitlan this would have strong religious connotations, but to the Europeans, it would come to symbolize the triumph of good over evil (with the snake sometimes representative of the serpent in the Garden of Eden).

At the center, the image of the reverse of colonial Mexico coin, 8 Reales 1783 (KM# 106), Charles III of Spain; at the upper side, parallel to the coin frame, the legend NUMISMATIC HERITAGE OF MEXICO; on the left side, the Mexican mint mark, while on the right field is the $100.

As of 1772, during the reign of Charles Carlos III, busted coins appeared in Mexico with a portrait of the monarch on their reverse sides after the fashion of European absolutism. In order to produce these coins, on March 18th, 1771, mint workers were secretly ordered to reduce the silver ore from eleven pieces (916.66 thousandths) to ten pieces twenty grains (902.77 thousandths), and at the same time the minting of coins of worlds and seas was suspended.