Like other precious metals, platinum is traded globally on various commodities exchanges. Trading is performed based on contracts for future delivery. The spot price of platinum is the current price that contract futures are being traded for potential delivery of a contract. As futures. most platinum and other precious metals are sold before it is mined or refined.
Platinum bullion dealers buy, sell and price their products in relation to the ask and buy spot prices. The spot price of platinum refers to the price of one troy ounce of platinum. Platinum bullion must be of a specific fineness in order to be accepted into LBMA or COMEX storage vaults.
The ask spot price is what people, commodity traders and bullion dealers is the platinum spot price that they will be selling at per ounce. The buy spot price is the price at which the same groups will be buying platinum.
The Troy weight is a system primarily used for measuring precious metals like silver, gold and platinum. One troy ounce is the equivalent of 31.1034768 grams. There are 12 troy ounces in a troy pound, rather than 16 ounces found in the 'avoirdupois' pound more commonly used for measuring weight in the United States.
The Troy Ounce, abbreviate as "t oz" or "oz t", is roughly 10% heavier than the avoirdupois ounce.
Many aspects of the troy weight system are derived from the Roman monetary system. Though the troy weight is believed to take it's name from the French town of Troyes. Troyes was a market town where the English and French began trading goods as early as the 9th century A.D. The Earl of Derby's written accounts of his travels throughout Europe in 1390 contain the first known written use of the troy weight system in describing the weight of a platter.