Intriguing diamonds of South African mine have “almost impossible” chemistry

Apparently contradictory materials are trapped together in two sparkling diamonds of a South African mine. The discovery casting light on how diamonds form.

A pair of diamonds that formed in hundreds of kilometers deep in Earth’s malleable cloak has traces of materials that form in completely opposite chemical environments – such an unusual combination that researchers thought that their coexistence was “almost impossible“.

The presence of these substances offers a window for the chemical processes of the cloak and the chemical reactions that form diamonds.

The two samples of diamonds were found in a South African mine. As with many other precious stones, they contain what they are called inclusions – Small fragments of surrounding rocks captured during the formation of diamonds.

These inclusions They are dismayed by most jewelersbut they constitute an exciting source of information for scientists.

This is especially true when diamonds form in the depths of the inaccessible cloak of the earth, because transport these inclusions unchanged to the surface – the only form that these minerals can rise hundreds of kilometers without being altered from their original state.

The two new samples of diamonds contain, each, inclusions of carbonated minerals rich in oxygen atomsa state known as oxidized, and poor oxygen nickel alloys – a state known as reduced in the language of chemistry.

Such as an acid and a base react immediately to form water and salt, oxidized carbonated minerals and reduced metals do not coexist for a long time.

Typically, the inclusions of diamonds show only one or the otherso their presence left perplexed Yaakov WeissFull Professor in Earth Sciences at the Hebrew University of Jerusalem, and his colleagues.

“Initially, we were confused and We put the samples aside For a year, confused, ”says Weiss to.

But when they re-examined the diamonds, the investigators realized that the inclusions had “Captured” an instant reaction that created the sparkling stones, confirming for the first time that diamonds can form when carbonated minerals and reduced metals in the cloak react.

These samples are the first case that scientists ever saw from the midpoint of this reaction captured on a natural diamond.

“It’s basically Have two sides of the oxidation spectrum“, Says Weiss, the main author of what describes the discovery, which was published on Monday in Nature Geoscience.

As it is deeper into the earth, the surface, the rocks and minerals become increasingly reducedwith fewer oxygen molecules available, but there is few direct evidence of this change from the cloak. Theoretical calculations gave scientists a notion of How the planet changes from oxidized to reduced with depth.

“We knew this reduction with some empirical data, with real samples up to perhaps 200 kilometers,” he says Maya KopylovaProfessor of Earth Sciences, at the University of British Columbia, who was not involved in the study, but wrote an editorial that accompanies the article.

“What happened below 200 km was just our idea, our models, because it is very difficult to get the materials. There are only a few samples of this depth,” says the researcher.

These new samples, with origin Entre 280 and 470 km below the earth’s surface, they now provide the First Factual Verification in the real world of theoretical chemistry of the Earth’s cloak.