Diamonds, messengers of the deep

Diamond is a mineral composed of carbon atoms arranged in a cubic crystal structure with extraordinarily strong covalent bonds that make it the hardest natural mineral in existence. Its hardness on the Mohs scale of 1 to 10 is 10, which is the maximum hardness. Interestingly, diamond has the same chemical composition as graphite, which is also made up of carbon atoms, but in this mineral the atoms are arranged in loosely connected sheets. For this reason, graphite has a hardness of just 1, making it one of the natural minerals with the lowest hardness.

 For a long time, diamond was particularly appreciated for being the mineral that had the highest hardness and thermal conductivity of all the materials known to man. These properties determined that the main industrial application of the diamond was in cutting and polishing tools and of course in jewelry.

The formation of natural diamonds requires very high temperatures and pressures. These conditions occur in limited areas of the Earth's mantle about 150 kilometers or more below the surface, where temperatures are at least 1050 degrees Celsius.

The critical environment of temperature and pressure for the formation and stability of diamond is present mainly in the Earth's mantle. Diamonds formed and stored in these "diamond stability zones" are transported to the Earth's surface during deep-seated volcanic eruptions. These eruptions rip off pieces of the mantle and quickly transport them to the surface. They are brought to the surface by deep volcanic eruptions that form ascending vents that in some cases can reach the surface. The main formations

 containing diamonds are kimberlite chimneys.

This type of volcanic eruption is extremely rare and has never been observed by modern humans.

Most of these chimneys do not contain diamonds, or contain only a small amount that are not of commercial interest. However, in the rare cases where they contain diamonds suitable for profitable mining, open pit and underground mines may be developed for their exploitation. On the surface, diamonds can disaggregate from the rock that contains them and be eroded, depositing in sedimentary layers of streams, rivers or coastal sands where they can be found and extracted and marketed.

In some circumstances, diamonds may contain inclusions of minerals that exist at great depths and that are not stable on the surface, and therefore normally inaccessible, but these inclusions allow them to be detected and studied.

Scientists from the University of Alberta (UBC) in Canada discovered particles of one of the most abundant minerals on the planet, but little known, encapsulated in a diamond at the Cullinan mine in South Africa. It is the calcium silicate perovskite. (CaSiO3)

Although the existence of this mineral was known theoretically, and it had even been possible to create it artificially, "nobody has ever managed to keep it stable on the surface of the Earth",

As we pointed out before, this mineral is believed to be found in large quantities in the lower mantle of the Earth, approximately 700 kilometers deep,

 However, a group of Canadian scientists found small particles of this mineral in a diamond mined less than a kilometer below the earth's crust.

This type of diamonds, formed at a depth of more than 500 km, are rare, since they usually form at a depth of 150-200 km, for that reason it was apparently possible to find calcium silicate perovskite that originate at a much greater depth.

Scientists from the University of Alberta highlighted the importance of this discovery, highlighting the unique characteristics of diamonds, which are "a window" to observe minerals such as CaSiO3, which are widely abundant in the depths of the planet, but due to their location totally inaccessible.

These types of diamonds are capable of withstanding a pressure of 24,000 million pascals, equivalent to 240,000 atmospheres, acting as a kind of 'elevator' for this type of mineral, housed in the depths of the earth.

This extremely rare mineral, almost nonexistent on the surface and extremely abundant at great depths, was named davemaoite in honor of the Chinese geologist Ho-Kwang "Dave" Mao, but technically it is called calcium silicate perovskite. Until now, scientists had only been able to replicate it synthetically in laboratories, because its formation only occurred at very high pressure and temperature.

If the mineral is put under other lower pressure conditions, it disintegrates, so scientists thought they would never be able to see it or have a sample.

But when it was inserted into a diamond, the product of immense pressures on carbon atoms, they were able to observe it, if only for a moment.

Using X-ray and mass spectroscopy analysis, University of Nevada geologists who also studied calcium silicate perovstkite said they detected it in a greenish rock that had been mined in the 1980s in Botswana.

By breaking the encapsulating diamond, the scientists literally had only a second to analyze the davemaoite, after which it turned into crystal.

"For jewelers and diamond buyers, size, color and clarity are important and inclusions, those black spots that bother the jeweler, are a gift to us," said one of the researchers when announcing this finding.

However, the data obtained in the process has allowed scientists to understand a little more about the composition and underground processes of the planet,

One of the team's geologists expressed

"For jewelers and diamond buyers, size, color and clarity are important and inclusions, those black spots that bother the jeweler, are a gift to us",