Precious metal "precious" metal can also be determined by high demand or market value. Precious metals in bulk form are known as bullion and are traded on commodity markets. Bullion metals may be cast into ingots or minted into coins. The defining attribute of bullion is that it is valued by its mass and purity rather than by a face value as money. The level of purity varies from issue to issue. "Three nines" (99.9%) purity is common. The purest mass-produced bullion coins are in the Canadian Gold Maple Leaf series, which go up to 99.999% purity. A 100% pure bullion is
Commodity market and (platinum). However, most ETCs implement a futures trading strategy, which may produce quite different results from owning the commodity. Commodity ETFs trade provide exposure to an increasing range of commodities and commodity indices, including energy, metals, softs and agriculture. Many commodity funds, such as oil roll so-called front-month futures contracts from month to month. This provides exposure to the commodity, but subjects the investor to risks involved in different prices along the "term structure", such as a high cost to roll. ETCs in China and India gained in importance due to those countries' emergence as commodities consumers and producers.