Mexico (2nd Republic). Silver Onza Coin.Mint Year: 1990 Reference: KM-494.2 Mint Place: Mexico (Mo) Denomination: Onza (Troy Ounze of Silver)Material: Silver (.999) Weight: 31.10gmDiameter: 36mm Mexico, officially the United Mexican States, is a federal constitutional republic in North America. It is bordered on the north by the United States of America; on the south and west by th ...