Why are diamonds found in kimberlite pipes?

Kimberlitic magmas form about 150 km below Earth’s surface, i.e. at much greater depths than any other volcanic rocks. The temperatures and pressures at such depths are so high that carbon can crystallize in the form of diamonds.

How do diamonds form in kimberlite pipes?

Mined diamonds that originate in the mantle are created when heat and pressure transform carbon. The mantle is nearly 100 miles below the Earth’s surface, and gems that come from the mantle are brought to the surface by kimberlite pipes, which are formed by deep-source volcanic eruptions.

How do kimberlite pipes work?

Kimberlite pipes are created as magma flows through deep fractures in the Earth. The magma inside the kimberlite pipes acts like an elevator, pushing the diamonds and other rocks and minerals through the mantle and crust in just a few hours.

Are all diamonds found in kimberlite?

Kimberlite is an igneous rock, which sometimes contains diamonds. … Kimberlite occurs in the Earth’s crust in vertical structures known as kimberlite pipes, as well as igneous dykes. Kimberlite also occurs as horizontal sills. Kimberlite pipes are the most important source of mined diamonds today.

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What conditions are needed for the formation of kimberlite diamonds?

The formation of natural diamonds requires very high temperatures and pressures. These conditions occur in limited zones of Earth’s mantle about 90 miles (150 kilometers) or more below the surface, where temperatures are at least 2000 degrees Fahrenheit (1050 degrees Celsius) [1].

What does a diamond in kimberlite look like?

kimberlite, also called blue ground, a dark-coloured, heavy, often altered and brecciated (fragmented), intrusive igneous rock that contains diamonds in its rock matrix. It has a porphyritic texture, with large, often rounded crystals (phenocrysts) surrounded by a fine-grained matrix (groundmass).

What is the relationship between diamonds and kimberlite?

study showed definitively that the diamonds had no genetic relationship to the kimberlite. This basic age relationship holds for all other diamondiferous kimberlites. Kimberlite eruptions, then, are just the way that diamonds make their way from depth in the mantle to Earth’s surface.

How do I know if I have a kimberlite?

The only way to absolutely identify one is by thin section and chemistry. And finding a kimberlite that contains diamonds is even rarer – most do not.

What gems are found in kimberlite?

Garnet, chromite, ilmenite, chromium diopside, and olivine occur in kimberlites in significantly higher quantities than diamonds. As kimberlite indicator minerals, they are used for diamond prospecting, as well as for the primary assessment of whether a target kimberlite is diamond-bearing or not.

How deep do kimberlite pipes go?

Kimberlites originate from >150 km depth within Earth’s mantle beneath thick continental roots, away from tectonic plate margins.

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How can you tell if a rock is a diamond?

The only hardness test that will identify a diamond is scratching corundum. Corundum, which includes all rubys and sapphires, is 9 on the hardiness scale. If your suspected diamond crystal can scratch corundum, then there is a good chance that you found a diamond. But NO OTHER HARDNESS TEST will identify a diamond.

What does a diamond look like when it’s found?

Diamonds found at the Crater are typically smooth and well rounded. Their shape resembles a polished stone with smooth sides and rounded edges. Size: The average size of a diamond is about the size of a paper match head, approximately 20-25 points weight.

What rock is diamond found in?

Diamond is only formed at high pressures. It is found in kimberlite, an ultrabasic volcanic rock formed very deep in the Earth’s crust. The extreme pressures needed to form diamonds are only reached at depths greater than 150km.

Are diamonds still being formed?

Diamonds may be ‘forever,’ but some may have formed more recently than geologists thought. A study of 26 diamonds, formed under extreme melting conditions in the Earth’s mantle, found two populations, one of which has geologically ‘young’ ages.

How much is kimberlite worth?

Modeled prices ranged between US$129 and US$355 per ct for the diamond populations of the major kimberlite units making up the Star and Orion South kimberlites.

How deep diamonds are found?

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).

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