Diamonds are not rare. Relative to other gemstones, they're actually pretty common. Scientists have even found ways to make them in the lab from all manner of carbon-containing matter. Like carbon dioxide, or various foodstuffs. Foodstuffs like peanut butter.

Photo Credit: Anna via flickr | CC BY-NC-SA 2.0

Geologist Dan Frost of Bayerisches Geoinstitut in Germany has been looking for ways to simulate the high pressure conditions of Earth's lower mantle. In the process, BBC Future reports, he's found some weird ways to make diamonds.

Frost hypothesizes that certain geological processes may draw carbon dioxide out of the world's oceans and down into the mantle, where high pressure converts it to diamond.The key ingredient for this to happen, he thinks, is iron. The high pressures of the mantle force carbon dioxide from the rocks into the iron-rich minerals, which strip away oxygen, leaving the carbon to form a diamond. And that is exactly what Frost found when he recreated the process using his presses – essentially forging a diamond from thin air.

Frost is hardly likely to make a fortune from his harvest; the diamonds take an agonisingly long time to grow. "If we wanted a two-or-three-millimetre diamond, we would need to leave it for weeks," he says. That hasn't stopped him experimenting with other sources for his diamond maker, however; at the behest of a German TV station, he attempted to create some diamonds from carbon-rich peanut butter. "A lot of hydrogen was released that destroyed the experiment," he says, "but only after it had been converted to diamond."

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