Troy Ounce

A troy ounce is a unit of measure used for weighing precious metals that dates back to the Middle Ages. Originally used in Troyes, France, one troy ounce is equal to 31.1034768 grams, according to the U.K. Royal Mint. One standard ounce, used to weigh other items such as sugar and grain, is slightly less at 28.35 grams. The troy ounce is retained even today as the standard unit of measurement in the precious metals market to ensure purity standards and other common measures remain consistent over time. The troy ounce is often abbreviated to read t oz or oz t.