Diamond Educatipn/History part IIII
Natural History/Formation
The formation of natural diamond requires very specific conditioning. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60-kilo bars. These conditions are known to be met in two places on Earth; in the lithosphere mantle below relatively stable continental plates, and at the site of a meteorite strike.
Diamonds formed in cratons
The conditions for diamond formatting to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140-190 kilometers (90-120 miles).
The correct combination of temperature and pressure is only found in the think, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist. Long residence in the cratonic lithosphere allows diamond crystals to grow larger.