Obverse: identify the front

The pictured regular Morelos peso has Mexican national arms, ESTADOS UNIDOS MEXICANOS and the visible 1960 issue date. The separately included 1957 Constitution design has its own commemorative portrait and legends. The national emblem alone cannot distinguish the .100 standard from other peso alloys.

Reverse: identify the back

Regular Morelos KM 459 has a right-facing armored bust within a wreath. The 1957 Constitution-centenary KM 458 instead has a left-facing head in its commemorative design. These are separate designs using the same nominal silver standard. Compare the design as well as the date when identifying a 1957 peso.

History and purpose

The .100 standard has much less silver than the .800, .720, .500 and .300 peso standards. Two distinct 1957 designs fit its nominal specifications: the regular KM 459 and commemorative KM 458. Later copper-nickel pesos must not be calculated as this 10%-silver type.

How to identify this variant

Match the complete 1 peso denomination and included issue years. The designated standard is 16 g gross mass, 0.1 silver fineness and 34.5 mm diameter. Keep unrelated alloys, gold coins, regional issues, patterns and replicas separate. Wear can reduce mass; appearance, a magnet or a household scale cannot alone determine precise alloy or authenticate the coin.

Understanding its metal content

Three matching coins contribute 48 nominal gross grams and 0.1542 reference fine silver troy ounces. The calculator uses 0.0514 oz per coin rather than treating total alloy mass as pure silver. Dollar melt pricing requires an approved current market quote; absent pricing is not shown as zero. Collector demand and condition remain separate from metal content.

Dates, varieties and composition changes

Actual annual years are 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966 and 1967. Regular KM 459 includes all eleven years. Constitution-centenary KM 458 is dated 1957 only. Both designs are included in the 1957 chronology, with the same 16 g gross mass, .100 fineness and 0.0514 reference fine silver troy ounce.

Melt value versus collector value

An attributed overdate, die variety, date, finish, condition or provenance may influence collector interest independently of silver content. The metal calculation cannot determine grade, rarity or collector value. Avoid polishing or cleaning; preserve original surfaces, any established provenance and reputable certification. A worn piece and an uncirculated example of the same nominal standard can have different collector values.

Authenticity and condition

A photograph of another denomination or alloy must not be used as this type’s illustration. Complete authentic obverse, reverse and edge views, measured mass and diameter help investigate a specimen but are not a silver assay. Plated pieces, cast copies, unlisted patterns and doubtful dates require individual attribution. Avoid cleaning or inferring a proof finish from shine.

Selling this coin

Sort 1 peso coins by complete date, design and nominal metal standard before entering quantities. Send clear photographs of both sides, plus edge photographs and measured weight where available, when requesting a CashForCoins appraisal. Preserve possible overdates and unusual die details for individual review. An offer can depend on authenticity, condition and collector demand alongside metal content. The reference melt calculation is an educational estimate.

Sources and calculation methodology

The reference’s designated World Silver melt reference supplies 16 g gross mass, 0.1 fineness and 0.0514 fine silver troy ounce. Matching dated KM 458 and 459 records supply actual dates, 34.5 mm diameter, identity, designs and mint notes. Thickness and identities of remaining alloy metals have not been independently verified. Actual annual years come from dated catalog rows rather than filling every year in a broad series heading. Overdates are counted under the visible issue year. The fine-silver reference applies to a correctly attributed coin; it does not establish authenticity, grade or collector value.

Photographs are attributed to their independently documented source. Small Banco de México images are reproduced at their original resolution under the institution’s published use permission, with attribution and source URL. A representative photograph does not authenticate or assay another specimen.

Common questions

References

• NGC designated World Silver Coin Melt Values — designated weight; fineness; reference silver ounces; broader group heading (checked 2026-10-12)
• NGC matching dated Mexican type KM 458 and459 — dated identity; weight; fineness; diameter; dates from actual annual rows; design; mint and variety notes; source precision differences where recorded (checked 2026-10-12)
• NGC matching dated Mexican type KM 458 and459 — dated identity; weight; fineness; diameter; dates from actual annual rows; design; mint and variety notes; source precision differences where recorded (checked 2026-10-12)
• Banco de México official coin photograph gallery — photograph source and published attribution; independent photo permission documented separately from currency-design copyright (checked 2026-10-12)
• Banco de México published reuse policy — institutional public use/reproduction permission requiring clear Banco source and URL; broad permission is not a CC license (checked 2026-10-12)

Issue-year references

• NGC designated World Silver Coin Melt Values
• NGC matching dated Mexican type KM 458 and459
• NGC matching dated Mexican type KM 458 and459
• Banco de México official coin photograph gallery
• Banco de México published reuse policy

Content maintained by CashForCoins. Last substantive record update: 2026-10-12. Report a specification or attribution issue through our contact page.

Related coins

Mexican .300 Silver Peso — 1950

Photo credits and rights on the linked coin profile.

Mexico • 30% silver; remaining alloy metals not independently verified

Issue years: 1950

Fine silver: 0.128600 troy oz

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