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Peanut Diamonds…More Than An Alchemist’s Dream?

Scientist David Frost from the Bayerisches Geoinstitute in Germany is mimicking conditions a thousand or so kilometres below the earth’s surface in his lab in order to turn peanuts into diamonds – and hopefully learn a bit more about the materials that make up our planet in the process.

Diamonds are made in the earth’s lower mantle, which is situated around 800-900 kilometres below the surface where temperatures are over 2200 degrees Celcius and the pressure is 1.3 million times higher than the air in our atmosphere. But the material composition of the lower mantle and the processes leading to diamond formation are not yet totally clear to scientists.

Frost’s theory of diamond formation was that in ancient times, rocks pulled carbon dioxide from the oceans. As the rocks were drawn into the lower mantle, high-pressure conditions caused the CO2 to escape from the rocks. Once the CO2 was released, iron in the lower mantle stripped it of its oxygen. The left over raw carbon was then pressed into a diamond as a result of the high heat and temperature. His theory followed that if he replicated these conditions in his laboratory, he could create a diamond of his own. Because all food products contain carbon, he chose a relatively simple source – peanut butter.

It turn out his hypothesis was right. By squeezing the peanut butter between two diamonds (one of the hardest materials on earth) and heating the material to around 1,093°C, Frost created his very own diamond.

But don’t expect to find any rings with peanut sourced diamonds yet. Not only are the diamonds slightly discolored due to impurities in the peanut butter, the method of creating these diamonds is slow, taking weeks to grow 3mm. Plus, hydrogen bonded to the carbon atoms are release after the diamond is formed, which can result in small explosions. But it is hoped the technique could lead to new technologies for making inexpensive, super-strong synthetic diamonds for industrial uses. Lacing these peanut diamonds with boron for example might result in semiconductors for electronics that don’t heat up when used – currently one the biggest wastes of energy in electronics.

And for Frost, the real value in the exercise lay not in creating cheaper diamonds but in figuring out a bit more about the materials that make up our planet. “If we want to understand how the Earth was formed, then one of the things you need to know is what planet is made out of,” he explains.

Source: BBC Future