A troy ounce is a unit of measurement commonly used to designate weights of certain precious metals such as silver or gold. One troy ounce is equivalent to 31.1034768 grams. One pound of gold is equal to 14.58 troy ounces.
A medieval practice of weighting, the troy ounce weights system originated in Troyes, France. The unit of measurement was one of the first imperial units — a measurement adopted by the British Empire
to create a unified weighting system. The troy ounce outweighs a regular, or avoirdupois, ounce by roughly 2.75 grams. To convert avoirdupois ounces to troy ounces, multiply the number of regular ounces by 0.911458333333. When the price of gold is reported, it is given in troy ounces.