Found in Botswana, the stunning almond-sized, 20.46-carat Okavango Blue Diamond is currently on display at the American Museum of Natural History’s new Mignone Halls of Gems and Minerals. More than a pretty gemstone, this diamond (found in 2018) is remarkable for its azure color which was created in an uncommon natural manner. While most diamonds contain more nitrogen than boron (which provides the blue hue), the Okavango Blue Diamond possesses the reverse, thanks to boron’s presence in seawater. Over time, that chemical element from the ocean is “recycled into the bedrock and Earth’s mantle through a process called subduction. When a tectonic plate in the ocean naturally collides with a continental one and slides underneath it, boron gets driven deeper down into the transition zone”—some 415 miles underground. Over time, those traces can then become part of a diamond. Geologist George Harlow (curator at the American Museum of Natural History’s Halls of Gems and Minerals) says that while they aren’t sure why the nitrogen is so low, this diamond is “another piece of evidence to support our interpretation of how the planet works.” Read more at Popular Science.
Image courtesy of Okavango Diamond Company