The Coinage of the First Mint of the Americas at Mexico City ...
During the investigation, Juan Gutirrez testified that quotthere had been cut and minted copper money in cuartos of four maravedes and two maravedes, and at present 1545 the blanks are being brought, ready cut, from Mechoacn... that the making of the blanks has been done in this manner for two years,4 more or less, by the Indians of Mechoacn, who are taught at this mint, and they make them from copper extracted from the Province of Mechoacn... that in this copper money no silver ...