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Harder-Than-Diamond Natural Carbon Crystals Found
HikingStick tips a piece from the science desk at MSNBC.com about a new, naturally occurring form of carbon found in a meteorite fragment. "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... [G]raphite layers were shocked and heated enough to create bonds between the layers — which is exactly how humans manufacture diamonds... [The research] 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."
The very end of the article suggests that they are harder than regular naturally occurring diamonds.
However, there is no way at the present to compare them to the artificial ultra-hard diamonds known as lonsdaleite and boron nitride, Ferroir said.
...do you think that the meteorite was made by magicians?
Space is natural too.
However, there is no way at the present to compare them to the artificial ultra-hard diamonds known as lonsdaleite and boron nitride, Ferroir said.
Boron nitride is not diamond at all, and lonsdaleite is described by Wikipedia as an allotrope of carbon that is found in meteorites and is harder than diamonds. Perhaps these people have just re-discovered something that was already known.
... not harder than natural diamonds.
That is because what they are (or should be) talking about is not hardness, but mechanical strength. Black diamonds are not harder, but because they consist of microscopic crystals, they don't have the convenient break lines of monocrystals, and therefore are more difficult to process. See:
http://www.sciencedaily.com/videos/2007/0612-mystery_diamonds.htm
The article mentions hexagonal diamond (lonsdaleite) as an artificial form of diamond, which it is with a very interesting low energy formation method, but it was first found in nature in the Canyon Diablo Meteorite in 1967. http://en.wikipedia.org/wiki/Lonsdaleite Pure lonsdaleite should be harder than regular diamond. I wish the article has said a little more about the crystal structure the researchers had found. That the energy required to make lonsdalite is low has interesting implications since the quantity needed to replace structural steel needs only about 1/280 of the energy needed to make the steel. http://mdsolar.blogspot.com/2008/01/anaximenes-way.html
They've got an odd definition of "diamond" there: boron nitride has no carbon in it. It's a chemical analogue of diamond, in that you turn half the C atoms (atomic number 6) into B (atomic number 5) and the others into N (atomic number 7). B-N compounds are fun analogues of C compounds but it's a bit of a stretch.
No kidding!!! What do you say at this point?
It's actually a reference to Spinal Tap, who made their amplifiers go up to eleven.
I'd rather you rationally disagree than irrationally agree.
One can also make diamonds harder by isolating and using heavier isotopes. A diamond of purified carbon-13 is harder than a mix of 12,13,14. Man-made diamonds can actually be harder than naturally occurring ones.
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Materials Science Feed @ Feed Distiller
Fullerite is formed from fullerene or buckyballs and is about twice as hard as diamond: http://en.wikipedia.org/wiki/Fullerene#Fullerite_.28solid_state.29
The Mohs hardness is ordinal, not linear, so until unless this item is added to the scale it will have an undefined Mohs hardness. Actual engineers use Brinell hardness or something similar.
For those that are interested in considering scientific paper without the media filter:
Ferroir, Tristan, Leonid Dubrovinsky, Ahmed El Goresy, Alexandre Simionovici, Tomoki Nakamura, and Philippe Gillet. 2010. Carbon polymorphism in shocked meteorites: Evidence for new natural ultrahard phases. Earth and Planetary Science Letters 290, no. 1-2: 150-154. doi:10.1016/j.epsl.2009.12.015. http://linkinghub.elsevier.com/retrieve/pii/S0012821X09007389.
I sure wish that secondary sources properly cited primary sources, even if they are only interviewing the main scientist involved. Giving the journal name and date as Discovery News did is a good step, though.
-Drache Kubisuro
found here
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V61-4Y4XCTH-3&_user=10&_coverDate=02%2F15%2F2010&_rdoc=18&_fmt=high&_orig=browse&_srch=doc-info(%23toc%235801%232010%23997099998%231609118%23FLA%23display%23Volume)&_cdi=5801&_sort=d&_docanchor=&_ct=26&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ae24ceb289eae1dcc9bc6870f3192dc2
And this is the abstract A slice of the Haverö meteorite which belongs to the ureilite class known to contain graphite and diamond was cut and then polished as a thin section using a diamond paste. We identified two carbonaceous areas which were standing out by more than 10 m in relief over the surface of the silicate matrix suggesting that the carbonaceous phases were not easily polishable by a diamond paste and would therefore imply larger polishing hardness. These areas were investigated by reflected light microscopy, high-resolution Field Emission SEM (FESEM), energy-dispersive X-ray (EDX) analysis, Raman spectroscopy, and were subsequently extracted for in situ synchrotron microbeam X-ray fluorescence (XRF), imaging and X-ray diffraction (XRD). We report here the natural occurrences of one new ultrahard rhombohedral carbon polymorph of the R3m space group which structure is very close to diamond but with a partial occupancy of some of the carbon sites. We also report the natural occurrence of the theoretically predicted 21R diamond polytype with lattice parameters very close to what has been modelized. These findings are of great interests for better understanding the world of carbon polymorphs and diamond polytypes giving new natural materials to investigate. These natural samples demonstrate that the carbon system is even more complex than what is currently thought based on ab initio static lattice calculations and high-pressure experiments since this new ultrahard polymorph has never been predicted nor synthesized.
But it wasn't a rock....it was a rock LOBSTER!!!