The Troy system is a system of measurement used primarily for precious metals, such as gold and silver. It is based on a pound that is divided into 12 ounces, with each ounce further divided into 20 pennyweights. This system helps standardize the trading and valuation of these metals in the market. The Troy ounce is the most commonly used unit in this system, weighing approximately 31.1 grams. The Troy pound, on the other hand, weighs about 373.24 grams. The system is named after the city of Troyes in France, where it was first used in the 14th century.