Africa – South Africa is the main producer of diamonds in Africa. Namibia is another country that produces diamonds Africa. Namibia is not a big producer as far as quantity is concerned, but its diamonds are of a high quality, 95% of the diamonds mined in Namibia’s Skeleton Coast are gem quality diamonds. Angola – as Namibia – is rich with alluvial deposits. A state-owned mining company carries out Angola’s mining, but because of many internal conflicts it is difficult to install a stable and regular marketing of the diamonds.
The diamond is a natural mineral composed mostly of carbon (99.95%). The diamond’s crystal structure belongs to the cubic system. The diamond is usually an octahedron and less often has the shape of a cube or a dodecahedron. The following conditions are needed to transform carbon into a diamond crystal: a pressure of 100,000 bars and a temperature of about 2,500ºC. Ambient conditions of this type only occur at depths of 130-200 kilometres below the surface of the earth in active volcanoes. Diamonds melting point is 3,700ºC, its specific gravity is 3.52, its hardness is 10 and its refractive index is 2.417.