quality:correction
Troy pound

A troy pound (abbreviated lb t) is equal to 12 troy ounces and to 5,760 grains, that is exactly 373.241 7216 grams. Troy weights were used in England by jewellers. Apothecaries also used the troy pound and ounce, but added the drachms and scruples unit in the apothecaries' system of weights.

Troy weight may take its name from the French market town of Troyes in France where English merchants traded at least as early as the early 9th century. The troy pound is no longer in general use or a legal unit for trade (it was abolished in the United Kingdom on 6 January 1879 by the Weights and Measures Act 1878), but the troy ounce, 1 ⁄ 12 of a troy pound, is still used for measurements of gems such as opals, and precious metals such as silver, platinum and particularly gold.