Formation of Diamonds

First, we must look at how diamonds form naturally in the earth. The primary “ingredient” in diamonds is pure carbon that has been exposed to pressure of 50,000 times the earth’s atmospheric pressure and temperatures of 2500°F. All of the transformation takes place in upper mantle of earth at depths of 200 miles below the surface as shown in Figure 1.1.(Diamond Formation, 2015)

Figure 1.1 Formation of Diamonds in the Upper Mantle

Figure 1.1 Formation of Diamonds in the Upper Mantle

Diamonds tend to form in 8 sided crystals but can also form in 12 sided crystals as well. No two diamonds are exactly the same, giving a variable value to each individual stone. They also vary in transparency, luster, dispersion of light, and color. Diamonds with low inclusions, white in color, and high refraction of light are more valuable than high inclusion, off white color, and low refraction of light diamonds. The variability of diamonds is also reflected in the style in which they form. There are three types of diamond deposits: Kimberlites, Lamproites, and Placer Deposits.

Kimberlite

The main form of diamond deposits are called kimberlites. Kimberlites are formed by a mixture of magma, minerals, rocks, and diamonds that create cone shaped pipes. These pipes are forced to the surface by volcanic activity and are found in lakes that were formed by inactive volcanic craters. The deposit is shaped like a champagne flute. The process is shown in Figure 1.2.(Kimberlite, 2015)

Figure 1.2 Kimberlite Diamond Formation

Figure 1.2 Kimberlite Diamond Formation

Lamproite

Another form of diamond deposits are called lamproites, which are formed like kimberlites except that boiling water and volatile compounds in magma corrode the overlaying rock. This results in a broader cone of diamond deposits at the surface. The deposit is shaped like a martini glass. The formation is shown in Figure 1.3.(Lamproite, 2015)

Figure 1.3 Lamproite Diamond Formation

Figure 1.3 Lamproite Diamond Formation

Placer Deposits 

The third form of diamond deposits are called placer deposits, which were formed by the erosion of diamond pipes millions of years ago. They are then transported by seasonal flooding and can be found by river sediment deposits. The formation is shown in Figure 1.4.(Placer Deposits, 2015)

Figure 1.4 Pacer Diamond Deposit Formation

Figure 1.4 Pacer Diamond Deposit Formation

The environmental impacts of the formation of diamonds is something that we cannot control. The earth produces this gem and uses natural geothermal processes like volcanic eruptions to bring the diamonds to the surface.

The underlying formation process is important in the next step of the diamond commodity chain, diamond mining.

The diamond industry fact sheet. (n.d.). Retrieved December 5, 2015, from
diamondfacts.org website: https://www.worlddiamondcouncil.org/download/
resources/documents/Fact%20Sheet%20(The%20Diamond%20Industry).pdf

Hussain, S. S. (2009, June 26). A diamond’s journey: On the cutting edge.
Retrieved December 5, 2015, from NBC News website: http://www.nbcnews.com/
id/15842527/ns/world_news/t/diamonds-journey-cutting-edge/#.VmOj0HarTIV

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