Global silver trade from the 16th to 18th centuries which China desired, so they traded silver to make up for their trade deficit. The two most important mining colonies of the Spanish Empire were Peru and Mexico, who were estimated to have provided one-hundred thousand tons of silver from the mid 16th Century to the end of the colonial period. The richest, and most productive mine in the Americas was that of Potosí in what is modern day Bolivia. The richest camp in Mexico was in the city of Zacatecas, however the production of this mine was far less than that of Potosi. More simplistic native mining techniques dominated
Aztec calendar stone in the next era. The duration of the ages is expressed in years, although they must be observed through the prism of Aztec time. In fact the common thing to figures 676, 364 and 312 is that they are multiples of 52, and 52 years is the duration of 1 Aztec century, and that is why they can express a certain amount of Aztec centuries. Thus, 676 years are 13 Aztec centuries; 364 years are 7, and 312 years are 6 Aztec centuries. Placed among these four squares are three additional dates, 1 Flint ("Tecpatl"), 1 Rain ("Atl"), and 7