Diamond of Hope, a rare blue diamond, is one of the most famous stones in history, with a complicated past passing from the hands of monarchs and bankers to the hands of heirs and thieves before moving to the Washington Museum, it.
The geological history of blue diamonds is even more complicated, according to a study that examines rare and precious stones published on Wednesday.
Scientists analyzed 46 blue diamonds, including one from South Africa that was sold for $ 25 million in 2016 and found that blue diamonds formed at least 660 km in depth, approaching the inner layer of the earth called the lower mantle. Small fragments of minerals, stuck inside diamonds, highlighted data on their origins.
Blue diamonds account for only 0.02 percent of diamonds extracted from the mines, but are some of the world's most famous stones.
Diamonds are a crystalline form of pure carbon and are formed under extreme heat and pressure. Blue diamonds crystallize near water-containing minerals, which were part of the ocean floor years ago, but dived deeper underground as a result of tectonic tile movements.
Scientists already knew that these diamonds benefited from the blue color of the boron element. This study suggests that the boron was once found in the ocean water and incorporated into the rocks of these oceans, which, after millions of years, were immersed deep underground.
"This is the first time anyone builds a story-based or fact-based model to find out how blue diamonds are formed. Prior to this study, we had no idea where they were formed, where they came from or where they found the boron, "said Evan Smith of Gemological Institute of America, who led the study published in Nature's journal Nature.
Most diamonds are not completely colorless, as they often have light yellow shades. Although rarely, some diamonds have strong shades of yellow, brown, pink or green. Nearly 99 percent of diamonds form 150-200 km underground, much shorter than the blue diamonds are formed.
In addition to the Diamond of Hope, which can be seen by anyone at the Smithsonian National Museum of Natural History, another famous blue diamond, called Oppenheimer Blue, was sold in 2016 to $ 57.5 million. At that time, it was the highest price offered at auctions for precious or jewelery.
"These diamonds are among the deepest," said Steven Shirey for the blue, geochemist of the Carnegie Institution for Science diamonds.
Source: Reuters
