The world's largest rough diamond.

The largest rough diamond ever found is called the Cullinan, discovered in South Africa in 1905.

The Cullinan rough diamond and the nine gemstones that split from it. Photo: Wikipedia

The Cullinan is a massive diamond weighing 3,106 carats and measuring 10.1 x 6.35 x 5.9 cm. That weight is equivalent to 621 grams, the size of a basketball or 7,692 bees, according to IFL Science .

On January 25, 1905, Frederick Wells, manager of the Premier mine in Pretoria, South Africa, saw a glint of light from something on the wall above him while 5.5 meters below ground. Wells retrieved the diamond and delivered it to Sir Thomas Cullinan, the mine owner, that same afternoon. However, no one was willing to buy the diamond named after Cullinan until 1907. Finally, the Transvaal provincial government acquired the gem as a birthday gift for King Edward VII of England. Worried it might be stolen during transport from Africa to London, King Edward arranged for a fake diamond to be placed on the steamship, surrounded by spies to mislead them, while Cullinan was sent to England in a simple box.

Because the Cullinan was too large to be kept in its original shape, King Edward entrusted the task of cutting the diamond to Joseph Asscher, head of the Asscher Diamond Company in Amsterdam. Asscher, who had previously cut the Excelsior, the 971-carat record-breaking diamond, studied the gemstone for six months before attempting a cut. In the first attempt, the steel blade broke while the diamond remained intact. In the second attempt, experts spent four days creating a 1.3 cm deep incision, allowing them to split the gemstone in two with a single tap. Asscher then fainted from exhaustion and extreme anxiety. For the next eight months, three people worked 14 hours a day to complete the splitting of the diamond. Ultimately, the Cullinan was cut into nine large stones, numbered I-IX, and nearly 100 smaller stones, worth millions of dollars.

The largest of them, named Cullinan I, also known as the Star of Africa, weighs 530.2 carats (106 g), equivalent to 32 tea bags. All nine large stones are owned by the British royal family, mostly used to decorate crowns and other jewelry such as necklaces.

The second largest diamond after the Cullinan is the Excelsior, found by miners at the Jagersfontein mine in South Africa in 1893. The Jagersfontein mine is home to two of the world's ten largest diamonds. The other, the Jubilee, weighs 245.35 carats.

An Khang (According to IFL Science/History )

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