2492-carat diamond unearthed in Botswana is the second-largest precious stone ever mined

Brides-to-be are quick enough to show off their sparklers even if their engagement rings boast gems a fraction the size of their knuckles.

But this huge diamond, the biggest found in more than a century, would be rather restrictive, as it’s fist-sized.

It was unearthed in Botswana, where the government says the 2,492-carat stone (one carat is 0.2 grams) is the second-largest ever mined.

The as-yet-unnamed half-kilo diamond was presented to the world yesterday at the office of president Mokgweetsi Masisi, one of the first to hold it.

Officials said it was too early to value it or decide how it would be sold.

Another smaller gem from the same Karowe mine was sold for $94 million in 2016, a record for a rough gem.

“This is history in the making,” said Naseem Lahri, Botswana managing director for Lucara Diamond Corp, the Canadian mining company that found it using X-ray technology.

“I am very proud. It is a product of Botswana.”

Its weight would make it the largest diamond found in 119 years since the 3,106-carat Cullinan diamond was discovered near South Africa.

A bigger, less pure black diamond was found in Brazil in the late 1800s, but it was above ground and thought to have been part of a meteorite.

Botswana, a country of 2.6 million in southern Africa, is the second-biggest producer of natural diamonds behind Russia and has unearthed all of the world’s biggest stones in recent years.

The Karowe mine has produced four other diamonds over 1,000 carats in the past decade.

Before this discovery, the Sewelo diamond, which was found at the same mine in 2019, was recognised as the second-biggest mined diamond in the world at 1,758 carats.

Diamonds are formed when carbon atoms are squeezed under pressure underground.