Carbon trade in both types of diamonds exists, the two markets act in dramatically different ways. Unlike precious metals such as gold or platinum, gem diamonds do not trade as a commodity: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. Industrial diamonds are valued mostly for their hardness and heat conductivity, with the gemological qualities of clarity and color being mostly irrelevant. About 80% of mined diamonds (equal to about 100 million carats or 20 tonnes annually) are unsuitable for use as gemstones are relegated for industrial
Commodity goods are also treated as commodities, e.g. human labour-power, works of art and natural resources ("earth itself is an instrument of labour"), even though they may not be produced specifically for the market, or be non-reproducible goods. Marx's analysis of the commodity is intended to help solve the problem of what establishes the economic value of goods, using the labor theory of value. This problem was extensively debated by Adam Smith, David Ricardo and Karl Rodbertus-Jagetzow among others. All three of the above-mentioned economists rejected the theory that labour composed 100% of the exchange value of any commodity. In varying