Raw diamond: a guide to natural diamonds from mines

Some gemstones are much rarer and much more coveted than others. Some continents have many deposits of precious stones and others do not. The exploitation of these deposits must be virtuous. And the ethical diamond must be a model in this field. We invite you to discover the world of raw diamonds. Where do these diamonds extracted from the mines come from? How are these diamond deposits mined?

The characteristics of the diamond

The raw diamond is a mineral that is composed of pure carbon. It is the precious stone whose composition is the simplest.

This gem was formed by the assembly in the 3 directions of space of carbon atoms.

The characteristics of the diamond are amazing. It has the highest hardness (10) of all minerals. It has a perfect cleavage plane, a density of 3.51 to 3.53, and a refractive index between 2.417 and 2.419.

There are diamonds of all colors, yellows and browns are the most many, and certain colors. Such as pinks, blues, reds, or greens are rare.

The natural diamond that is mined has nothing to do with the synthetic diamond that is created by man.

The diamond has been mined for over 3000 years in the mines of India in the Golconda region.

Even today, mining companies exploit these diamondiferous deposits. And produce millions of carats of diamonds each year.

Diamond crystal morphology

The diamond crystallizes in the cubic system, here are its main raw forms:

• the octahedron has 8 triangular faces, 12 edges, and 6 vertices.
• the dodecahedron has 12 pentagonal faces, 30 edges, and 20 vertices.
• the cube has 6 faces, 12 edges, and 8 vertices.
• the rhombododecahedron has 12 rhombic faces, 24 edges, and 14 vertices.

Geology and prospecting for natural diamonds

The raw diamond was formed in the bowels of the earth. The carbon was subjected to enormous pressures, extreme temperatures, and depths of 150 km. All this for millions of years.

These raw diamond crystals were then expelled by volcanic eruptions. They rose through chimneys to the surface of the earth forming volcanic rocks.

Natural erosion then unearthed these precious stones and millions of years later man discovered these gems.

There are 2 kinds of diamondiferous deposits:

• Primary deposits: these are chimneys (pipes) that contain kimberlite or lamproitic rocks.
• Secondary deposits: erosion alters the kimberlitic rock. The diamonds end up in the waterways and are dispersed throughout their course.

There are several methods for exploring diamondiferous zones, we can cite:

• Prospecting large areas: we are not looking for diamonds. But for minerals or satellite materials. Such as ilmenite, which is present in larger quantities than diamonds. One can also look for the raw diamond on the coasts or the littoral. Where the diamond has been driven by the rivers to the ocean.
• Prospecting linked to hydrography: diamonds are sought in the alluvial gravels of rivers. But very often these areas are difficult to access. In Africa, due to the rainy season, exploration can only be done in the dry season.

Ore processing and raw diamond recovery

• Artisanal exploitation: these are very small exploitations. That is located in African countries or South American countries. These craftsmen use barges, motor pumps, pickaxes, sieves, sluices, etc. Diamond recovery is manual.
• Semi-industrial farm: small semi-industrial farms located in Africa or South America. They use automatic raw diamond laundries which have flow rates between 15 m3/h and 200 m3/h. Diamond recovery is manual or semi-automated.
• Industrial exploitation: exploitations that have technical means are much more important than the 2 other modes of exploitation. Geological studies have been conducted. An operating permit has been filed with the Ministry of Mines for a period of 20 to 25 years. Important infrastructures have been built. Roads, bridges, treatment plants, schools, etc. Diamond recovery is automated and fully secure.