Carat (mass) g or possibly up to 5 g less. Therefore, the metric equivalent of 1 "siliqua" was approximately 189 mg. The Greeks had a similar unit of the same value. Gold fineness in carats comes from carats and grains of gold in a solidus of coin. The conversion rates 1 solidus = 24 carats, 1 carat = 4 grains still stand. Woolhouse's "Measures, Weights and Moneys of all Nations" gives gold fineness in carats of 4 grains, and silver in pounds of 12 troy ounces of 20 pennyweight each. Carat (mass) The carat (ct) (not to be confused with the karat,
Troy weight was based on the tower pound, which is of a troy pound.) The "d" in "dwt" stands for "denarius", the ancient Roman coin that equates loosely to a penny. The symbol "d" for penny can be recognized in the notation for British pre-decimal pennies, in which pounds, shillings, and pence were indicated using the symbols "£", "s", and "d", respectively. For example, "£6 11s 8d" indicated six pounds, eleven shillings, and eight pence. Mint weights, also known as "moneyers' weights" were legalised by Act of Parliament dated 17 July 1649 entitled "An Act touching the monies and coins of England".