Mexican Silver Eagle Mark Marks: How to Identify and Date Them

A small spread-eagle punch, almost always accompanied by a number stamped inside or beside it identifying the registered assayer/workshop, often paired with a numeric fineness mark (e.g. '.925') and/or the words 'Mexico' or 'Hecho en Mexico.'

• 1948-c.1955: Mexico adopts the national eagle assay-mark system, though enforcement is initially limited.
• c.1955-1979: The eagle-plus-number system is enforced widely, with different registered numbers assigned to different assay districts and individual workshops (e.g., Mexico City, Taxco, and specific named workshops).
• After 1994 (current regulation): Under the current official Mexican standard, marking requirements center on a numeric fineness mark, a 'contraste' (assay) determination, a country-of-origin mark, and a maker's registration mark/number rather than the eagle system specifically.

The style of the eagle stamp itself is a rough dating clue -- earlier strikes tend to be crisp and detailed, while examples from the 1970s are often shallower and more simplified -- but this is a stylistic observation rather than a documented, government-defined dating chart.

• A blurry or malformed eagle stamp with an implausible registration number, especially on thin/lightweight metal, is a warning sign of a fake; spurious signatures added to plain silver and 'married' pieces assembled from unrelated fragments are also common problems.
• Alpaca (a nickel-based base-metal alloy with no silver content) is sometimes fraudulently sold or marked as if it were genuine Mexican silver.
• The unqualified phrase 'Mexican silver' with no accompanying purity number should be treated with caution, since legitimate pieces normally carry an explicit fineness mark.

The official Mexican standard fetched directly for this research (a 1994/1995 Diario Oficial de la Federacion notice, precursor to NOM-033-SCFI-1994) confirms the regulatory concept of 'contraste' (fineness determination) and marking requirements, but its retrievable text did not itself describe the eagle symbol or specific registered eagle numbers -- those details rely on a specialist antique-reference site as the source and should be treated as supplementary-tier pending confirmation from an official Mexican government archive (e.g., a Diario Oficial decree specifically establishing the eagle system) or a museum source.

Turn the piece over and light the mark from a low angle with a lamp or phone torch, which throws the impressed or engraved lines into relief; a printed or painted mark wants soft, even light instead. Fill the frame with the mark, then take a second shot of the whole piece. Do not clean tarnish off silver before photographing; the mark reads better dark. The app matches the mark and shape to the notes above.