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Troy weight is a system of units of mass customarily used for precious metals and gemstones. It derives from the troy system of mass, which dates back to before the time of William the Conqueror. Its name comes from the city of Troyes in France, an important trading city in the Middle Ages.A troy ounce, the only currently used unit of the system, is 480 grains, somewhat heavier than an avoirdupois ounce (437.5 grains). A grain is exactly 64.798 91 mg, hence one troy ounce is exactly 31.103 476 8 g, about 10 per cent more than the avoirdupois ounce, which is about 28.3 g. The troy ounce is the only ounce used in the pricing of precious metals, such as gold and silver, and this is the only remaining use of the troy ounce. In troy weight, there are 12 ounces in a poundOfficially the pound is the name for at least three different units of mass: the pound (avoirdupois the troy pound the obsolete imperial pound There also exists an unofficial metric pound . While most standards bodies define the pound as a unit of mass, m, rather than 16 in the more common avoirdupois system.
A troy pound is 5760 grains (about 373.24 g), rather than 7000 (about 453.59 g).
This provides the technical curiosity that an ounce of gold weighs more than an ounce of feathers, but a pounds of gold weighs less than a pound of feathers.
| Unit | Grains | Grams
|
| Pound (12 ounces) | 5760 | 373.241 72
|
| Ounce (20 pennyweight) | 480 | 31.103 477
|
| Pennyweight | 24 | 1.555 173 8
|
| Grain | 1 | 0.064 798 91
|
See also
- CaratCarat or Karat may refer to: a unit of mass for gems. See Carat (mass). carat almost exclusively means the unit of mass. a unit of purity for gold. See Carat (purity). karat almost exclusively means the unit of purity. Karat is also a variety of banana fo
- Conversion of unitsThis article lists conversion factors between a number of units of measurement. Key: definition exactly equal to approximatively equal to Length Area Volume Angle Mass In physics, the pound of mass is sometimes written lbm to distinguish it from the pound.
Units of mass
