Carbon

In nature, inorganic carbon is found in the Earth's crust, ~270 ppm [4]. The isotopes found in nature are ¹²C (98.892 %, stable) and ¹³C (1.108 %, stable) [4].

In pure solid form, carbon exist in the following forms:

Diamonds are found in South Africa, Zaire, the Gold Coast, Beazil, and Arkasas, USA [5].

Carbon in the form of graphite is mined in Mexico, Madagascar, Ceylon and Canada [5].