Troy weight A grain is 20 mites, a mite is 24 droits, a droit is 20 perits, a perit is 24 blanks. In Scotland, the Incorporation of Goldsmiths of the City of Edinburgh used a system in multiples of sixteen. ("See Assay-Master's Accounts, 1681–1702, on loan from the Incorporation to the National Archives of Scotland".) Thus, there were 16 drops to the troy ounce, 16 ounces to the troy pound, and 16 pounds to the troy stone. The Scots had several other ways of measuring precious metals and gems, but this was the common usage for gold and silver. The Pound was
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".