Coin silver is a silver alloy composed of 90 per cent pure silver and 10 per cent copper, expressed as a fineness of .900. The designation derives from its long association with United States coinage: American silver coins minted before 1965 were struck to this standard, and silversmiths of the 18th and 19th centuries routinely melted circulating coins as a convenient, reliably assayed source of metal. The result was a distinct tradition of American flatware, hollowware, and occasional jewellery fabricated to the .900 standard rather than to the British sterling mark of .925.

Composition and properties

The 10 per cent copper addition serves the same purpose as in sterling silver — hardening an otherwise too-ductile metal — but at a slightly lower proportion than sterling's 7.5 per cent copper. Coin silver is consequently marginally softer than sterling and fractionally more susceptible to tarnish, since the copper component oxidises in the presence of sulphur compounds in the atmosphere. The difference in working hardness is modest and would not have been decisive for most smithing applications; the practical advantage of coin silver was simply the ready availability of a known-purity feedstock in the form of legal tender.

Historical context

American silversmiths of the Federal and early Republic periods — working in centres such as Boston, New York, and Philadelphia — operated without a centralised hallmarking system comparable to the British assay-office network. Maker's marks were stamped at the craftsman's discretion, and purity was not legally enforced. Melting coin provided a de facto quality guarantee. Pieces from this era are often marked simply with the maker's surname or initials, sometimes accompanied by the word COIN, PURE COIN, DOLLAR, or STANDARD — all indicating .900 silver. These marks are now among the diagnostic features used by appraisers and auction specialists to date and attribute American silver.

The adoption of sterling as the dominant American commercial standard accelerated through the latter half of the 19th century, particularly after Tiffany & Co. and other major manufacturers publicly committed to the .925 mark. By the early 20th century, coin silver had largely retreated from mainstream production, surviving chiefly in rural or regional workshops and in the output of smaller silversmiths who continued to work from melted coinage.

Identification in estate and antique pieces

When evaluating estate silver, the distinction between coin and sterling is relevant to both metallurgical and historical assessment. X-ray fluorescence (XRF) analysis provides a non-destructive means of confirming fineness. Visually, coin silver often displays a slightly warmer, more yellow-toned surface than sterling, though this is an unreliable guide in isolation. The presence of period maker's marks and the characteristic verbal purity stamps noted above remain the most useful documentary evidence. Pieces should be assessed in conjunction with a reputable reference such as the standard American silver marks catalogues used by auction specialists.

Contemporary status

Coin silver is rarely specified in new jewellery or silversmithing commissions. Sterling silver (.925) is the prevailing standard in contemporary Western markets, while higher-purity alloys such as Britannia silver (.958) and fine silver (.999) occupy specialist niches. Coin silver's significance today is essentially historical: it defines a body of American decorative arts and domestic silver spanning roughly 1750 to 1900, and its identification remains a practical concern for estate appraisers, auction cataloguers, and collectors of American antique silver.