<P> French silver made for export carries an assay mark in the shape of the head of Mercury, along with a number to indicate the millesimal fineness: "1" for . 920, "2" for . 840 and "3" for . 750 . </P> <P> French silver also is punched with the mark of the maker . </P> <P> In the early United States, no national assaying system was adopted, although the city of Baltimore did maintain its own assay office between 1814 and 1830 . Prior to the general adoption of sterling silver as the standard of purity in 1868, silver was generally obtained from the melting of coins . Since these could vary considerably in purity, from around . 750 millesimal fineness to around . 900, silver known as "coin silver" varies in purity . Silver at that time was sometimes marked "COIN" or "PURE COIN", but can also be without a standard mark altogether . After the adoption of the sterling standard, pieces were marked with "STERLING", the number "925" or the notation "925 / 1000". </P> <P> The United States also had no date marking system . Because of this, some companies within the U.S., such as Tiffany and Gorham, adopted their own date marking systems . </P>

When did they start using 925 on silver