Mexico 1 Onza 1979

Mexico 1 Onza 1979 Obverse: Coin mint called 'de balancín' (of sway), used in Mexico City Mint to make their first coins. This device uses the rotation of a pole on top with weight on a side to get enough speed to force a spiral down and mint the coin (later updated to use steam and then electric motor but the method was the same; with the issuer name around the rim and the date to the left. Reverse: Scale as a centerpiece with the weight as legend around; the purity at the top-left; and the weight in grams at center bottom; and mint under. Silver 33.72g. Edge Reeded. KM M49