A troy ounce is a unit of weight commonly used to measure precious metals like gold, silver, and platinum. It is part of the troy weight system, which dates back to the Roman Empire and was later adopted in medieval England. One troy ounce is equivalent to approximately 31.1035 grams. The troy ounce differs from the more commonly used avoirdupois ounce, which is about 28.35 grams. This distinction is important for investors and traders in the precious metals market, as prices are typically quoted in troy ounces. Understanding this measurement helps ensure accurate transactions involving gold, silver, and other valuable commodities.