Deep beneath our feet, in pockets of the Earth's lithosphere that geologists call cratons, there may be more than a thousand trillion (or a "quadrillion") tonnes of diamond, according to a study conducted by a team that includes researchers from MIT and Harvard.
Deep beneath our feet, in pockets of the Earth's lithosphere that geologists call cratons, there may be more than a thousand trillion (or a "quadrillion") tonnes of diamond, according to a study conducted by a team that includes researchers from MIT and Harvard.
Diamonds, despite their mesmerising sparkle, are made of the same stuff at the tip of your pencil: Carbon atoms. The best-known property of the diamond crystal, perhaps, is its hardness -- but it was a very different characteristic that helped the study's authors reach their conclusion.
Here's the gist of the account provided by a Massachusetts Institute of Technology (MIT) report: Sound waves were found to travel at an unexpectedly quick pace in cratonic roots, so the researchers put together "virtual rocks, made from various combinations of minerals" to determine what kind of substance could generate these speeds. There was just one match -- one that "contains 1 to 2 per cent diamond".
So now, what was that key property of diamonds we were talking about? Sound, the scientist Ulrich Faul told MIT News, travels twice as quickly through this carbon structure "as in the dominant mineral in upper mantle (a part of the lithosphere) rocks, olivine."
The study's methodology is fascinating, but how can we be absolutely sure that there's a massive, hidden trove of diamond down there?
"Its circumstantial evidence, but we've pieced it all together...We went through all the different possibilities, from every angle, and this is the only one that's left as a reasonable explanation, MIT News quoted Faul as saying.
Diamonds, despite their mesmerising sparkle, are made of the same stuff at the tip of your pencil: Carbon atoms. The best-known property of the diamond crystal, perhaps, is its hardness -- but it was a very different characteristic that helped the study's authors reach their conclusion.
Here's the gist of the account provided by a Massachusetts Institute of Technology (MIT) report: Sound waves were found to travel at an unexpectedly quick pace in cratonic roots, so the researchers put together "virtual rocks, made from various combinations of minerals" to determine what kind of substance could generate these speeds. There was just one match -- one that "contains 1 to 2 per cent diamond".
So now, what was that key property of diamonds we were talking about? Sound, the scientist Ulrich Faul told MIT News, travels twice as quickly through this carbon structure "as in the dominant mineral in upper mantle (a part of the lithosphere) rocks, olivine."
The study's methodology is fascinating, but how can we be absolutely sure that there's a massive, hidden trove of diamond down there?
"Its circumstantial evidence, but we've pieced it all together...We went through all the different possibilities, from every angle, and this is the only one that's left as a reasonable explanation, MIT News quoted Faul as saying.