Botswana’s Karowe mine recently produced a record breaking 2,492-carat diamond, the largest diamond unearthed in over a century. It’s the biggest in a line of massive stones that have come out of the mine in the last several years. As the stone, named Motswedi, awaits a price, the find is a reminder of the strange marriage between geology and economy.
Lucara-owned Karowe diamond mine is famous for producing large stones. Photo: Lucara
How to find massive diamonds
The largest diamond ever found was pulled from the earth in South Africa in 1905, then under British colonial rule. British officials gifted the 3,106-carat Cullinan Diamond to King Edward VII, who had it cut into nine pieces and added to various crown jewels. The pieces are still there today, alongside other large pieces extracted, or outright stolen, from colonial holdings, like the Koh-i-Noor.
Such was the fate of the largest-ever diamond. But all of the runners-up have come from Karowe. In 2019, they found Sewelô, a 1,758-carat gem sold to Louis Vuitton for an unknown amount. In 2015, the mine unearthed the 1,111-carat stone known as Lesedi La Rona. Why does this region, and this mine in particular, produce so many exceptionally large diamonds?
Diamonds are made of compressed carbon, formed deep beneath the Earth in the mantle. They’re brought up to the crust, where we can mine them, through the eruption of kimberlite volcanoes. As the magma moves explosively upwards, it picks up diamonds and carries them to the surface. Meteor strikes can also create diamonds, but they are small and not of gem quality.
In Botswana and South Africa, the land is rich in kimberlite pipes due to ancient volcanic activity.
In addition to their geological advantages, Lucara has a technological trick: X-rays. An X-ray camera system in the mine measures the atomic density of material. The very dense diamonds stand out against the normal rock, and miners can retrieve them unbroken.
A diamond suspended in kimberlite. This piece was mined in South Africa. Photo: Wikimedia Commons
Making diamonds pay
Since opening in 2012, the Karowe mine in Botswana has produced hundreds of notably large, gem-quality diamonds. But mineral wealth isn’t always easy to translate into material wealth, at least for the country from which it is extracted.
In Botswana, the government is considering legislation that will ensure more of the profit from its massive diamonds goes back into the country itself. It’s also trying to diversify its economy. Diamonds may be forever, but deposits aren’t endless. Amidst growing fear that diamond deposits will bottom out, Lucara has acquired permission to move the Karowe mine operations deeper underground in the coming decades.
But for now, they have the world’s second-largest gem-quality diamond on their hands, and no one is quite sure how much it’s worth. Lucara has partnered with Belgian firm HB Antwerp, which told French outlet Agence France-Presse that it was hard to put a price on the gem.
The monetary value of a diamond is hard to judge, since it’s all made up. Perfect diamonds can be grown cheaply in the lab, and the rarity of diamonds is partially artificial and sustained by an intense centuries-long marketing campaign by the De Beers corporation.
So, how much is the second-largest diamond ever found worth? Whatever some chump is willing to pay for it.
