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 be longer than the time spent on the same commodity by a skilled worker. Thus, under this analysis, the commodity produced by an unskilled worker would be more valuable than the same commodity produced by the skilled worker. Marx pointed out, however, that in society at large, an average amount of time that was necessary to produce the commodity would arise. This average time necessary to produce the commodity Marx called the "socially necessary labour time" Socially necessary labour time was the proper basis on which to base the "exchange value" of a given commodity. Value and price are not