Carbon Crystals in Meteorite Harder than Diamond

Scientists have discovered carbon crystals inside a meteorite that crashed in Finland that are harder than naturally-occurring diamonds. The re-entry impact and heat are probably responsible for this unusual formation:

The researchers were polishing a slice of the carbon-rich Havero meteorite that fell to Earth in Finland in 1971. When they then studied the polished surface they discovered carbon-loaded spots that were raised well above the rest of the surface –- suggesting that these areas were harder than the diamonds used in the polishing paste.

“That in itself is not surprising,” said diamond researcher Changfeng Chen of the University of Nevada in Las Vegas. He explained that sometimes during the shock of impact graphite can create jumbled “amorphous” zones that can resist diamonds, at least those coming at them from one direction.

But what apparently happened in the Havero meteorite is that graphite layers were shocked and heated enough to create bonds between the layers — which is exactly how humans manufacture diamonds, Chen explained.

Ferroir’s team took the next step and put the diamond-resistant crystals under the scrutiny of some very rigorous mineralogical analyzing instruments to learn how its atoms are lined up. That allowed them to confirm that they had, indeed, found a new “phase” or polymorph of crystalline carbon as well as a type of diamond that had been predicted to exist decades ago, but had never been found in nature until now.

Link via Popular Science | Photo: Apollo Diamond by flickr user jurvetson, used under Creative Commons license