How are Natural Diamonds formed?
Contrary to popular belief, coal has rarely, if ever played a role in the formation of diamonds. 3 billion years ago deep within the Earth’s crust under conditions of intense heat and pressure that cause carbon atoms to crystallize forming diamonds. The formation of natural diamonds requires very high temperatures and pressures, and there are 4 known ways this can happen in nature.
- Diamond Formation in Earth's Mantle The most common way natural diamonds are formed is in the earths crust under very specific conditions. These conditions occur in Earth's mantle more than 90 miles below the surface, where temperatures are at least 2000 degrees Fahrenheit. These Diamonds are delivered to the earths surface during volcanic eruptions.
2. Diamond Formation in Subduction Zones During the plate tectonic process where the earth’s plates collide, one plate is forced down into the mantle. As this plate descends it is exposed to increasing temperature and pressure. Diamonds have been found in rocks that are thought to have been sub ducted and then returned to the surface.
3. Diamond Formation at Impact Sites When these asteroids strike the earth, extreme temperatures and pressures are produced. The high temperature and pressure conditions of such an impact are more than adequate to form diamonds. This theory of diamond formation has been supported by the discovery of tiny diamonds around several asteroid impact sites.
4. Formation in Space Diamonds have been discovered in some meteorites. These diamonds are thought to have formed in space in response to asteroid impacts or other severe events.