The mark on gold or silver articles after they have been assayed. Every article in gold is compared with a given standard of pure gold. This standard is supposed to be divided into twenty-four parts called carats; gold equal to the standard is said to be twenty-four carats fine. Manufactured articles are never made of pure gold, but the quantity of alloy used is restricted. Thus sovereigns and wedding-rings contain two parts of alloy to every twenty-two of gold, and are said to be twenty-two carats fine. The best gold watch-cases contain six parts of silver or copper to eighteen of gold, and are therefore eighteen carats fine. Other gold watch cases and gold articles may contain nine, twelve, or fifteen parts of alloy, and only fifteen, twelve, or nine of gold. The Mint price of standard gold is £3 17s. 10½d. per ounce, or £46 14s. 6d. per pound.
Standard silver consists of thirty-seven parts of pure silver and three of copper. The Mint price is 5s. 6d. an ounce, but silver to be melted or manufactured into “plate” varies in value according to the silver market. To-day (Oct. 20th, 1894) it is 291/2d. per ounce.
Suppose the article to be marked is taken to the assay office for the hall mark. It will receive a leopard's head for London; an anchor for Birmingham; three wheat sheaves or a dagger for Chester; a castle with two wings for Exeter; five lions and a cross for York; a crown for Sheffield; three castles for Newcastle-on-Tyne; a thistle or castle and lion for Edinburgh; a tree and a salmon with a ring in its mouth for Glasgow; a harp or Hibernia for Dublin, etc. The specific mark shows at once where the article was assayed.
Besides the hall mark, there is also the standard mark, which for England is a lion passant; for Edinburgh a thistle; for Glasgow a lion rampant; and for Ireland a crowned harp. If the article stamped contains less pure metal than the standard coin of the realm, the number of carats is marked on it, as eighteen, fifteen, twelve, or nine carats fine.
Besides the hall mark, the standard mark, and the figure, there is a letter called the date mark. Only twenty letters are used, beginning with A, omitting J, and ending with V; one year they are in Roman characters, another year in Italian, another in Gothic, another in Old English; sometimes they are all capitals, sometimes all small letters; so, by seeing the letter and referring to a table, the exact year of the mark can be discovered. Lastly, the head of the reigning sovereign completes the marks.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894