The origin of investment diamonds

  • The Cullinan mine
  • From kimberlite to investment diamonds
  • The exploitation process of diamonds

The Cullinan Mine

The Cullinan mine is the only operational diamond mine in the world open to visitors. This South African mine site, also known under the official name of Premier Mine, is situated near to Pretoria and the Kimberley Mine known from the Kimberley-Process. This site is worldwide renown partly thanks to the uncovering of the largest rough diamond ever found, the Cullinan diamond. This 3106.75 carat gemstone was discovered in 1905 and the biggest part (The Great Star of Africa) was incorporated in the British crown jewels, exposed in the Tower of London. Ever since the Cullinan Mine is globally known for its clear investment diamonds.

From Kimberlite to investment diamonds

Before investment diamonds can be traded, they go through a labour-intensive process. Investment diamonds are extracted from kimberlite, also known as ‘blue ground’. This is an ultramafic vulcanic igneous rock formed under high pressure up to 450 km deep into the earth’s crust. Kimberlite is the most important source of natural diamonds.

Through time, kimberlite gets pushed upwards, forming a sort of pipe, surrounded by the mantle. The high concentration of carbon in the pipe results in the preservation of the crystal structure. For processing rough kimberlite into good investment diamonds, the diamond pipe needs to be mined from the surface to the bottom, deep in the earth.

The mining process of diamonds

When kimberlite gets discovered on the surface, it is necessary to assess first whether demining is profitmaking or not, since only 1 to 200 kimberlite diamonds have the right quality. Subsequently, a deep tunnel is bored next to the kimberlite pipe, while on strategic locations the mantle gets separated from the kimberlite by means of explosives. Afterwards jackhammers break the exploded lumps of kimberlite into little pieces until they are ready for transport and further processing.

An underground transporting system brings pieces of kimberlite to the cranes, bringing the raw materials to the surface. During the processing of kimberlite, compression is used to separate the diamonds from the kimberlite. When the kimberlite is almost processed to mud, the raw materials are treated with paraffin and bee wax, making the rough diamonds visible. Finally, these diamonds are collected, weighed, sold and processed until they can be sold as investment diamonds on the international market.

The demining process of diamond is extremely complex and fascinating at the same time. The process from rough kimberlite to investment diamonds is very complex, having quality as main concern. BNT Diamonds offers various options for diversification of your investment portfolio. For professional and objective advice, please contact us.

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Author: Daan Deruyter
Source: BAUNAT

With this article, BAUNAT strives to inform you thoroughly about investing in diamonds. No investment can be guaranteed to be without risk or fully according to your expectations. That is why we recommend to research the risks and aspects of investing in diamond properly to ensure that you make the right choice for your portfolio.


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