The true blue of sparklers

– The Hope Diamond, a rare blue diamond that is one of the world’s most famous jewels, has had a complicated history, passing through the hands of monarchs, bankers, heiresses and thieves before landing for all to see at a Washington museum.

The geological history of blue diamonds is even more complex, according to research published yesterday.

Scientists analysed 46 blue diamonds, including one from SA that sold for $25 million (R330 million) in 2016, and determined they can form at depths of 660km.

Blue diamonds comprise only about 0.02% of mined diamonds but include some of the world’s most famous jewels.

Scientists already knew these diamonds acquired their blue hue from the element boron. The study indicated this boron once had been in ocean water and was incorporated into the seafloor rock that over millions of years moved deep underground.

“This is the first time anyone has come up with a fact-based story or model for how blue diamonds form,” said research scientist Evan Smith, who led the study published in the journal Nature.

Aside from the Hope Diamond, on display at the Smithsonian National Museum of Natural History, another diamond, the Oppenheimer Blue, in 2016 sold for $57.5 million. – Reuters

Washington