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 chain metaphor for this concept because things are interconnected in so many ways, not just a mere straight line. This source explains global commodity chains in depth. Commodity chain A commodity chain is a process used by firms to gather resources, transform them into goods or commodities, and finally, distribute them to consumers. It is a series of links connecting the many places of production and distribution and resulting in a commodity that is then exchanged on the world market. In short, it is the connected path from which a good travels from producers to consumers. Commodity chains can be unique