Troy Weight
a system of weights used for gold, silver, platinum, and precious stones. The Troy pound contains 12 ounces, 240 pennyweights, and 5,760 grains, being thus less than the avoirdupois pound, which contains 7,000 grains. The old apothecary's weight, which had the same value of pound as the Troy, but subdivided into 12 ounces, 96 drachms, and 288 scruples, was abolished in Great Britain and the new apothecary's weight made the same as the avoirdupois. The name Troy was given to the standard pound in 1495. The origin of the name is doubtful, some deriving it from "Troy Novant," the monkish name of London, others from Troyes in France.