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
Purity and Danger Purity and Danger Purity and Danger: An Analysis of Concepts of Pollution and Taboo is a 1966 book by the anthropologist and cultural theorist Mary Douglas. It is her best known work. In 1991 the "Times Literary Supplement" listed it as one of the hundred most influential non-fiction books published since 1945. It has gone through numerous reprints and re-editions (1969, 1970, 1978, 1984, 1991, 2002). In 2003 a further edition was brought out as volume 2 in "Mary Douglas: Collected Works" (). The line of inquiry in "Purity and Danger" traces the words and meaning of dirt in different