This grinding stone is a relic of the ancient silver mining industry of New Spain, now the independent Republic of Mexico, in the sixteenth through the early nineteenth centuries, miners from the Town of Real De Angeles used beasts of burden to pull this and similar stones in a circular path. Weighing three tonnes, this stone crushed the ore to the fine particles required in the next step, separation of the silver by mercury amalgamation. The stone was presented to Equity Silver Mines Limited on July 21, 1985 by its sister Silver Mine, Minera Real De Angeles, Zacatecas, Mexico whose people visited Equity to study Canadian mining practices while their mine was under construction.