Washington: Scientists have found crystals in a meteorite that are even harder than diamonds.
According to a report in Discovery News, the finding was made by Tristan Ferroir and his team from the Universite de Lyon in France.
A closer look with an array of instruments revealed two totally new kinds of naturally occurring carbon, which are harder than the diamonds formed inside the Earth.
"The discovery was accidental but we were sure that looking in these meteorites would lead to new findings on the carbon system," said Ferroir.
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.
Among the things that would be interesting to learn, Chen said, is how hard the new kinds of diamonds are.
The sample from the meteorite was far too small to test for hardness, except to show that it is certainly harder than regular diamonds.
"The only evidence we have for a higher hardness than diamond is the fact that we polished the rock section with a diamond paste and that our polymorph and polytypes were not polished by this material," said Ferroir.
"This why we do think that its hardness is harder than diamond," he added.