International Rough Diamond Week Wows with 1,000-Carat Diamond

The Isreal Diamond Exchange (IDE) recently kicked off their first International Rough Diamond Week, scheduled to run until March 13th. Participants include representatives from major international mining companies such as De Beers, Rio Tinto, and ALROSA, who will have the opportunity to view a wide variety of rough diamonds, including 600- and 1,000-carat offerings from Tzoffey’s 1818 and a nearly 30-carat vivid blue rough diamond from Cora International.

While jewelry consumers may salivate at the thought of a thousand-carat stone, it’s important to remember that many different factors come into play when deciding how to cut a rough diamond, such as overall dimensions and location of any flaws or blemishes. In fact, 30-60% of a rough stone’s original weight is lost upon cutting.

“With Diamonds, the larger the diamond, the more rare it is,” explains Jonathan Mervis, Head of Business Development at Mervis Diamond Importers. “If you cut it into 1,000 pieces, you’d no longer have a rare diamond. You’d want to make sure that you cut it into as few pieces as possible. The truth is that every diamond is entirely unique. I’m sure any woman would love a diamond like that!”

What happens to the pieces of the original rough diamond that aren’t used for the final polished piece? Since miners must move nearly 40,000 pounds of earth in order to recover a rough one-carat diamond, even the leftover pieces are valuable.

Only about one in every five rough diamonds is considered “gem quality”, so the decision to cut and polish large stones is not made lightly. Buyers are paying for potential, and once a cut is made, the fate of the stone is forever fixed. The rough blue featured at IDE’s International Rough Diamond Week was bought by Cora International for over $864,000 per carat, or $25.6 million total. Who knows what it might sell for when — and if — it’s ever cut?


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