By Michelle Graff
This 302.37-carat square-shaped emerald-cut diamond is the biggest of the 67 stones cut by Graff from Lesedi La Rona, the second largest rough diamond ever found.
New York—Graff has unveiled the principal polished diamond cut from Lesedi La Rona, the 1,109-carat chunk of rough discovered in Botswana in 2015.

It is a square emerald-cut stone that weighs 302.37 carats and is the largest diamond ever graded by the Gemological Institute of America as being of highest color, D, and “highest clarity.” A Graff spokeswoman could not confirm the diamond’s exact clarity grade by press time Wednesday.

The stone, which has been named the Graff Lesedi La Rona, also holds the distinction of being the largest square emerald-cut diamond in the world, the company said.

Laurence Graff (no relation to author), who’s become known as the modern-day Harry Winston for handling many of the largest and most spectacular diamonds of the last century, called crafting the Graff Lesedi La Rona “an honor.”

“This diamond, our diamond, is beyond words,” he said.

20190410 Graff holding stoneLaurence Graff, founder of Graff Diamonds International Ltd., holding the 302.37-carat Graff Lesedi La Rona. The diamond took more than 18 months to make, from planning to final polishing.

Workers for Lucara Diamond Corp. found the 1,109-carat rough diamond (originally 1,111 carats before cleaning) at the Karowe mine in November 2015.

A naming contest open to all Botswana citizens was held a few months later and Thembani Moitlhobogi submitted the winning moniker, which means “Our Light” in Tswana, the official language of Botswana.

Lucara put the stone up for auction at Sotheby’s in June 2016 but bidding failed to reach the reserve price of $70 million, so the stone went unsold until Graff stepped forward in September 2017. The company paid $53 million, or about $48,000 per carat, for Lesedi La Rona.

Chipping Away
Before he even purchased the diamond, Graff had some idea how cutting the Lesedi La Rona would go.

In May 2017, the London-based diamantaire bought a 373.72-carat chunk of rough thought to have chipped off Lesedi La Rona, so he knew the stone could result in “sensational” polished diamonds.

Even so, Lesedi La Rona’s size presented a challenge to Graff’s gemologists because they had never analyzed a stone of that size. Lesedi La Rona is the second largest gem-quality rough diamond on record, topped only by the 3,106-carat Cullinan, which was discovered in 1905.

The tennis ball-sized diamond was too big for the company’s existing equipment, so a scanner had to be custom built with brand new imaging software.

Using the new software, the gemologists mapped the stone’s imperfections to plot which cuts would yield the largest and highest clarity diamonds possible, and received a challenge from their boss that was thought impossible when first examining the stone: find a way to create a 300-carat polished diamond from Lesedi La Rona.

WATCH: The Cutting of Lesedi La Rona

The analysis continued for months before gemologists moved forward with a plan for cutting and polishing the diamond. Laurence Graff described the task of cutting a diamond of this size as “the riskiest form of art.”

“You can never add and you can never cover up a mistake, you can only take away,” he said. “You have to be careful, and you have to be perfect.”

The initial cutting was done with lasers, while the following shaping and faceting was done by hand. The company said polishing the table facet alone took “hundreds of hours.”

All told, a little more than 18 months elapsed between the time Graff bought the diamond in September 2017 and when his gemologists and craftsmen finished polishing its final facets.

20190410 LesediLaRonaThe 1,109-carat Lesedi La Rona in its rough state. Though it cannot be proven beyond doubt, GIA researchers strongly believe that the diamond weighed more than 2,700 carats at one point, as it is thought the 812.77-carat “Constellation” along with a 373-carat rough and 296- and 183-carat chunks all broke off this same stone.

Neither the asking price for the Graff Lesedi La Rona nor its current location are being disclosed.

Fragments from the cutting of the stone were donated to the Smithsonian Institute to help its advanced diamond research, as the Lesedi La Rona has been identified by GIA as being a “superdeep” diamond, a stone that, like blue diamonds, formed three times deeper in the earth than other diamonds.

The Graff Lesedi La Rona is one of 67 diamonds cut from the 1,109-carat rough, the first of which were unveiled late last year.

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