Peak uranium gold, silver, copper or nickel, uranium is not widely traded on an organized commodity exchange such as the London Metal Exchange. It is traded on the NYMEX but on very low volume. Instead, it is traded in most cases through contracts negotiated directly between a buyer and a seller. The structure of uranium supply contracts varies widely. The prices are either fixed or base on referenced to economic indices such as GDP, inflation or currency exchange. Contracts traditionally are based on the uranium spot price and rules by which the price can escalate. Delivery quantities, schedules, and prices vary from
Commodity market trading, such as the purity of gold in bullion. Classical civilizations built complex global markets trading gold or silver for spices, cloth, wood and weapons, most of which had standards of quality and timeliness. Through the 19th century "the exchanges became effective spokesmen for, and innovators of, improvements in transportation, warehousing, and financing, which paved the way to expanded interstate and international trade." Reputation and clearing became central concerns, and states that could handle them most effectively developed powerful financial centers. In 1934, the US Bureau of Labor Statistics began the computation of a daily Commodity price index that became