Beyond Rare: The Two-of-a-Kind Diamond

Rare is a relative term.  Compared to most other minerals, diamonds are rare. Among all the diamonds ever mined, those of exceptional size, clarity and color are highly-prized.

But beyond run-of-the-mill rare is a super-league of rarity. Like the chameleon diamonds I mentioned last week, that change color when heated, and are very, very rare. Or the newly-discovered cryogenic diamonds, which do likewise when chilled. Even rarer.

Rare, however, is nothing compared to unique. Imagine holding a diamond in your hand that is unlike any other in the known world. Like the incredible diamond-within-a-diamond unearthed two years ago and dubbed the Matryoshka after the traditional Russian doll. That truly was one of a kind. I say "was" because it now has a friend, making it two of a kind.  Funny isn't it, you get no double diamonds for a billion of years, then two in two years. 

The new discovery was made at the Ellendale alluvial deposit, in Western Australia, by India Bore Diamond Holdings (IBDH). The near-colorless 0.844 carat diamond has a cavity. Inside it is a tiny diamond - unmeasured as yet but possibly just 0.01-ct - that can freely roll around inside. This new Matryoshka diamond is significantly larger than the original one, which weighs 0.62-cts and which was discovered by Alrosa during sorting at its Nyurba division in Yakutia. The new stone - a flat, triangular mackle - also displays a distinctive purple fluorescence under UV light, like many diamonds found at Ellendale.  It was discovered in a newly-identified paleo-channel deposit being mined by IBDH, which holds exclusive leases in the southern part of the extensive Ellendale field.

"The diamond was recovered from a small test sample at our Ellendale L Channel mine and its basic details were recorded and catalogued and it was sent to our lab along with many others for some detailed analysis," IBDH director Patrick Stringer told me.

"The stone was not recognized at the mine as anything extra-special and it was only at the sorting room and later at the lab that the true rarity of the stone was recognized by our specialists.  They couldn't really believe it when they first saw it!

Collectors will pay 50 times over the odds, maybe even more, for a Matryoshka, compared with a "regular" stone with the same 4Cs. There's no benchmark so it's hard to say. But for the time being IBDH says it's more interested in the science than any possible sale.

"There is a great deal of interest from collectors of course but the stone will be retained for some time yet for further study," said Patrick.

"It has created a great deal of excitement, to be fair, mostly for its scientific value and extreme rarity rather than for its potential as a cut diamond.

"We will soon release some further information on the stone as we are doing some more analysis on whether it is two stones, one (perhaps very much older) captured by the other or indeed the same stone that has had quite a unique pattern of episodic growth.

"Either way there is quite a lot that this one stone may add to the industry's knowledge and theories around natural diamond formation."

Experts still have a lot of work to on Matryoshka diamonds. The GIA lab in New York examined the first one a few months after it was revealed and came up with a possible explanation.

They suggested that over time - millions or billions of years - about 0.11 carats of diamond material had dissolved away through two small etched channels that extended from the surface of the diamond to the internal cavity.

The diamond material that remained formed into a small diamond crystal of 0.03 carats that is entirely detached from the host crystal - and has a natural clear green body color, with "Christmas-tree"-like etchings on its surface. 

"We have never seen anything like this," said Tom Moses, GIA's executive vice president and chief laboratory and research officer at the time.

"This is a truly unusual diamond, not only for the fact that there is a small diamond crystal inside, and entirely detached from the host crystal, but also for the mystery of how this diamond-in-a-diamond formed."

Now that there's a second example to work with, maybe we're a little closer to answering some questions.

Have a fabulous weekend.