Silverino back with ya,
The Onza was first made in 1949. Then again in 1978 thru 1980
Obverse (Front):
The "de balancín" (Balance), 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.
Example of it in use pictured below.
The 1949 Onza pictured above.
The Reverse (Back):
Scale as center piece. With ounce weight in legend around. Fineness at top-left. Weight in grams at center bottom. LEY (Law) .925 Sterling 33.625 Peso (Weight). More than ounce of weight but 1 oz of Silver.
Reverse pictured below.
The key date (fecha clave) is the 1978 pictured below
Everyone thinks the 1949 is the key date, nope. Casa de Moneda de Mexico produced one million 1949's
Mintages:
1978.........................................280,000 (Wide spacing between DE MONEDA; Type 1)
1978.....................................................(Close spacing between DE MONEDA; Type 2)
1979......................................4,508,000 (Close spacing between DE MONEDA; Left scale pan points to U in UNA; Type 3)
1979.....................................................(Close spacing between DE MONEDA; Left scale pan points between U and N of UNA; Type 4)
1980......................................6,104,000 (Left scale pan points to the U of UNA; Type 5)
42mm Diameter
Reeded Edge
Coin alignment ↑↓ 1978-80
BU = Brilliantly Uncirculated (Brilla Sin Circulado)
UNC = Uncirculated
AU = About Uncirculated (Casi Circulado)
Free to ReSteem