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
Pennyweight Act of 1878; only the Troy ounce and its decimal subdivisions remained official. The Troy ounce enjoys a specific legal exemption from metrication in the UK. The pennyweight is the common weight used in the valuation and measurement of precious metals. Jewellers use the pennyweight in calculating the amount and cost of precious metals used in fabricating or casting jewellery. Similarly, dentists and dental labs still use the pennyweight as the measure of precious metals in dental crowns and inlays. Pennyweight and grains are still used to weigh gooseberries in competitions in Cheshire, northwest UK. Over the Pennines in Yorkshire