Pennyweight Troy weights were defined in such a way that the old Tower pound came out to exactly 5400 Troy grains (also known as barleycorns), the Tower pennyweight Troy grains (and thus approximately 1.46 grams). After 1527, the English pennyweight was the Troy pennyweight. of 24 Troy grains. Thus the Troy pound, ounce, and pennyweight, with their definitions given in terms of the Troy grain instead of in terms of the Tower grain, were 1/15 or 6.667% more than the Tower equivalents. The Troy pound and the pennyweight lost their official status in the United Kingdom in the Weights and Measures
Troy weight on the continent. The troy ounce and grain were also part of the apothecaries' system. This was long used in medicine, but has now been largely replaced by the metric system (milligrams). The only troy weight in widespread use today is the British Imperial troy ounce and its American counterpart. Both are currently based on a grain of 0.06479891 gram (exact, by definition), with 480 grains to a troy ounce (compared with grains for an ounce avoirdupois). The British Empire abolished the 12-ounce troy pound in the 19th century, though it has been retained (although rarely used) in the American