Silver Bullion coinage
Over the centuries Mexico has been one of the world’s largest silver producers. It was always competitive in the silver trade-dollar market with the Liberty Cap 8 reales and Liberty Cap pesos, which were discontinued in 1909. In 1949, in an attempt to reestablish itself in world trade-dollar activities, Mexico issued the “Una Onza” (One ounce) coin, following up with issues from 1978 through to 21980. In 1982, Mexico instituted the silver Libertad program, which continues to the present day.
Una Onza
Onzas have no legal tender status. All are 41 mm in diameter, with a reeded edge. The obverse of the onza features the historic screw-press design, while the reverse bears a balance scale.
Type 1
KM-M49a 1949 1oz
Mintage was 1,000,000 in 1949.
Type 2
Mintage was
| Year | Mintage | |
| 1978 | 280,000 | type 1, type 2 |
| 1979 | 4,508,000 | type 3, type 4 |
| 1980 | 6,104,000 | 0/2, 80/70 |
KM-M49b.1 1978 1 oz type1
Type 1: wide space (3 mm) between the words in DE MONEDA
KM-M49B.2 1978 1oz type 2 (close spacing) (Stack’s-Bowers auction, 16 May 2025, Lot 76598)
Type 2: close space (2.75 mm) between the words in DE MONEDA
KM-M49B.3 1979 1oz type 3 (Stack’s-Bowers auction, 16 May 2023, Lot 70675)
Type 3: left pan of scales points to U in UNA
KM-M49B.4 1979 1oz type 4 (Stack’s-Bowers auction, 3 June 2022, Lot 72157)
Type 4: left pan of scales points between U and N in UNA
KM-M49b.5 1980 1 oz type 5
Type 5: 1980 date with type 3 reverse
For further details on the onzas, see Scott Doll's article here.
Type 3 - El Capricho
Struck on the same dies as the 1978-1980 official issues, the 1989 Proof El Capricho does not appear in the official mintage reports: the unofficial estimate is that fewer than 50 were struck.
Bullion Commemorative Series
In 1987 and 1988 the Casa de Moneda de México produced the Bullion Commemorative Series: privately issued pieces struck under contract with a Texas coin dealer, with an obverse design slightly different from the design used on the official bullion pieces.
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