Diamond
Diamonds are made deep in the Earth where there is an intense amount of pressure and heat. The formation of natural diamonds needs specific conditions. These are exposure of carbon-bearing materials to high pressure, between 45 and 60 kilobars (4.5 and 6 GPa), but at a comparatively low temperature, between about . These conditions are found in two places on Earth: in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.