Photo credit: ALROSA

A loose diamond within a diamond

Nature never stops providing the extraordinary, unexpected and unique.

This natural gift is not recent. To be fair, this “diamond within a diamond” is more than 800 million years old, but humans have only been aware of it for a span of months.

The adamantine oddity was unearthed at an open-pit mine 200 miles north of Nyurba, Russia last October. Specialists of the Yakutsk Diamond Trade Enterprise discovered they had an unusual 0.62 carat freak of nature on their hands during the sorting process and immediately passed it to ALROSA’s Research and Development Geological Enterprise.

Photo credit: ALROSA

A different “loose diamond”

Dubbed the “Matryoshka” in honor of Russia’s wooden nesting dolls, the motion of the small loose diamond nested within another diamond can be seen in this darkfield video.

The scientists of ALROSA’s R&D Geological Enterprise used several advanced methods to study the diamond – including Raman and infrared spectroscopies as well as X-ray microtomography – and developed a hypothesis regarding its formation.

According to Deputy Director Oleg Kovalchuk:

The most interesting thing for us was to find out how the air space between the inner and outer diamonds was formed. We have two main hypotheses. According to the first version, a mantle mineral captured a diamond during its growth, and later it was dissolved in the Earth’s surface. According to the second version, a layer of porous polycrystalline diamond substance was formed inside the diamond because of ultra-fast growth, and more aggressive mantle processes subsequently dissolved it. Due to the presence of the dissolved zone, one diamond began to move freely inside another on the principle of matryoshka nesting doll.

This x-ray image shows the void around the diamond crystal, floating within another crystal.

Photo credit: ALROSA

It’s estimated that approximately 0.11 carats of diamond dissolved through two small channels extending from the inner cavity to the diamond’s surface. That left a 0.03 carat diamond crystal which is entirely detached and moves freely within the outer shell.

The entire diamond within a diamond weighs 0.62 carats and has outer dimensions of 4.80 x 4.90 x 2.80 mm. The internal cavity has a volume of 6 cubic mm and the internal crystal volume is 1.6 cubic mm. That inner diamond has a tabular shape and dimensions of 1.9×2.1×0.6 mm.

Photo credit: ALROSA

According to Kovalchuk:

As far as we know, there were no such diamonds in the history of global diamond mining yet. This is really a unique creation of nature, especially since nature does not like emptiness. Usually, some minerals are replaced by others without cavity formation.

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John Pollard

John Pollard is a subject matter expert for diamond producers, grading laboratories and jewelers in the USA, Europe and Asia. He has lectured for JCK Las Vegas, IGI workshops in Hong Kong, Beijing and Shanghai, the American Gem Society in Washington D.C., GIA's Alumni Association and other industry organizations. He is the US Director for Crafted by Infinity diamonds.

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