Diamonds in the Ground

Diamonds are formed in magmas 200 km below the surface of the earth, which corresponds to an extremely high pressure. In combination with a high temperature, above 1400°C, this has caused diamond formation from magmas containing carbon. 

Diamonds are also found in placers. These so-called secondary deposits are formed when kimberlite weathers to a yellowish soil, which is transported away by water and glaciers. Placers are important sources of natural industrial diamonds. 

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