The Diamond

They make diamonds of carbon, so they form as carbon atoms under a high temperature and pressure; they bond together to start growing crystals. … That’s why a diamond is such a hard material because you have each carbon atom participating in four of these very strong covalent bonds that form between carbon atoms. Lab-grown diamonds take approximately 6 to 10 weeks to develop in a laboratory. Diamonds close enough to earth’s surface to be mined today, formed in nature between 1 billion to 3.3 billion years ago. Due to the immense pressure that is present in this part of the earth, as well as the extreme temperatures, a diamond gradually forms. The entire process takes between 1 billion and 3.3 billion years, which is approximately 25% to 75% of our earth’s age.

Diamonds are found at a depth of approx. 150-200km below the surface of the Earth. Here, temperatures average 900 to 1,300 degrees Celsius and at a pressure of 45 to 60 kilobars (which is around 50,000 times that of atmospheric pressure at the Earth’s surface). Under these conditions, molten lamproite and kimberlite (commonly known as magma) also formed within the Earth’s upper mantle and expand at a rapid rate. This expansion causes the magma to erupt, forcing it to the Earth’s surface and taking along with it diamond-bearing rocks. Moving at an incredible speed, the magma takes the path with the least resistance, forming a ‘pipe’ to the surface.

As it cools the magma hardens to form Kimberlite and settles in vertical structures known as kimberlite pipes. These kimberlite pipes are the most significant source of diamonds, yet they estimate that only 1 in every 200 kimberlite pipes contain gem-quality diamonds. The name ‘Kimberlite’ derived from the South African town of Kimberley where the first diamonds found in this type of rock.