Re: [meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond
This article seems to be lacking in two parts. As already stated, the pressure from atmosphere entry is too low to create diamonds. The second part I reacted to was the statement The crystals were raised more than 10 µm above the polished surface, which meant they were harder than the diamonds in the polishing paste. That is plainly wrong. If a hard mineral like ordinary diamonds is embedded in a softer material, for example some silicate minerals then the silicates will be removed at a faster pace than the harder diamonds which rises above the surrounding surface. Maybe it's just a problem with the interpretation of the original article by the physorg writer Oh, I think it is. The abstract never claims higher hardness than diamond, ... were not easily polishable by a diamond paste and would therefore imply larger polishing hardness. I guess that the part about atmosphere is also an error made by physorg, not the original researcher. I read it as ... larger polishing hardness [than surrounding material]. Original abstract at : http://www.sciencedirect.com/science?_ob=ArticleURL_udi=B6V61-4Y4XCTH-3_user=10_coverDate=02%2F15%2F2010_rdoc=1_fmt=high_orig=search_sort=d_docanchor=view=c_acct=C50221_version=1_urlVersion=0_userid=10md5=d8d1010a5c82833bfc75265887d7cf8a Too bad I can't access the full article. :-( /Göran Ron Baalke wrote: http://www.physorg.com/news184402061.html Meteorite yields carbon crystals harder than diamond by Lin Edwards physorg.com February 3, 2010 (PhysOrg.com) -- Two new types of ultra-hard carbon crystals have been found by researchers investigating the ureilite class Haverö meteorite that crashed to Earth in Finland in 1971. Ureilite meteorites are carbon-rich and known to contain graphite and diamonds. The super-hard diamonds were created when graphite in the meteorite experienced the intense heat and pressure of entering the Earth's atmosphere and crashing into the ground. The graphite layers would have been heated and shocked enough to create bonds between them, in much the same way as humans manufacture diamonds. The new carbon crystals were too small to test for precise hardness but they are known to be harder than normal diamonds because the researchers found them by using a diamond paste to polish a slice of the meteorite. The crystals were raised more than 10 µm above the polished surface, which meant they were harder than the diamonds in the polishing paste. The researchers had seen carbon crystals that resisted the diamond polishing in one direction before, but the new crystals were unaffected when polished in every direction. The scientists then used an array of mineralogical instruments, including microscopy, spectroscopy and energy-dispersive X-rays among others, to study the structure of the crystals. This allowed them to identify them as representing two new carbon polymorphs or diamond polytypes. One is an ultra-hard rhombohedral carbon polymorph similar to diamond, while the other is a 21R diamond polytype ultra-hard diamond. The existence of ultra-hard diamonds had been predicted decades ago, but they have never before been found in nature. The novel form consists of fused graphite sheets similar to artificial diamond. Professor Tristan Ferroir, leader of the research team from the Université de Lyon in France, said the discovery was accidental, but they had thought an examination of the meteorite would lead to new findings on the carbon system. Professor Ferroir said there is currently no way to compare the structure of the new crystals to boron nitride and lonsdaleite, the artificially manufactured ultra-hard diamonds, but the findings help scientists gain a better understanding of carbon polymorphs and give them new materials to investigate and perhaps synthesize. They also show the carbon system is more complex than previously thought. The findings on the new diamond were published in the Earth and Planetary Science Letters journal on February 15. More information:* http://dx.doi.org/10.1016/j.epsl.2009.12.015 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond
http://www.physorg.com/news184402061.html Meteorite yields carbon crystals harder than diamond by Lin Edwards physorg.com February 3, 2010 (PhysOrg.com) -- Two new types of ultra-hard carbon crystals have been found by researchers investigating the ureilite class Haverö meteorite that crashed to Earth in Finland in 1971. Ureilite meteorites are carbon-rich and known to contain graphite and diamonds. The super-hard diamonds were created when graphite in the meteorite experienced the intense heat and pressure of entering the Earth's atmosphere and crashing into the ground. The graphite layers would have been heated and shocked enough to create bonds between them, in much the same way as humans manufacture diamonds. The new carbon crystals were too small to test for precise hardness but they are known to be harder than normal diamonds because the researchers found them by using a diamond paste to polish a slice of the meteorite. The crystals were raised more than 10 µm above the polished surface, which meant they were harder than the diamonds in the polishing paste. The researchers had seen carbon crystals that resisted the diamond polishing in one direction before, but the new crystals were unaffected when polished in every direction. The scientists then used an array of mineralogical instruments, including microscopy, spectroscopy and energy-dispersive X-rays among others, to study the structure of the crystals. This allowed them to identify them as representing two new carbon polymorphs or diamond polytypes. One is an ultra-hard rhombohedral carbon polymorph similar to diamond, while the other is a 21R diamond polytype ultra-hard diamond. The existence of ultra-hard diamonds had been predicted decades ago, but they have never before been found in nature. The novel form consists of fused graphite sheets similar to artificial diamond. Professor Tristan Ferroir, leader of the research team from the Université de Lyon in France, said the discovery was accidental, but they had thought an examination of the meteorite would lead to new findings on the carbon system. Professor Ferroir said there is currently no way to compare the structure of the new crystals to boron nitride and lonsdaleite, the artificially manufactured ultra-hard diamonds, but the findings help scientists gain a better understanding of carbon polymorphs and give them new materials to investigate and perhaps synthesize. They also show the carbon system is more complex than previously thought. The findings on the new diamond were published in the Earth and Planetary Science Letters journal on February 15. More information:* http://dx.doi.org/10.1016/j.epsl.2009.12.015 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond
Hi list, This is off topic (sort of) to this very interesting post but it does mention graphite and diamonds. I have shared this observation before and every time I have mentioned it I have been taken wrong! Has any else noticed how the graphite inclusions in the fossil EL3, NWA 2828, 2965, Al Haggounia 001 etc. fool an electronic diamond tester? Now this is the part I have been taken wrong on, I'm not saying I have found testable size diamonds but rather the graphite will set off an electronic diamond tester! Those testers operate on thermal conductivity. I can take my optical scopes to 2000X but that is no help in this stuff. I have tried similar inclusions in other meteorites and nothing. Is the inclusion made of nano diamonds or just a material that is as thermally conductive as diamonds? Which ever, it is interesting! Tom Phillips In a message dated 2/3/2010 6:23:57 P.M. Mountain Standard Time, baalke @zagami.jpl.nasa.gov writes: http://www.physorg.com/news184402061.html Meteorite yields carbon crystals harder than diamond by Lin Edwards physorg.com February 3, 2010 (PhysOrg.com) -- Two new types of ultra-hard carbon crystals have been found by researchers investigating the ureilite class Haverö meteorite that crashed to Earth in Finland in 1971. Ureilite meteorites are carbon-rich and known to contain graphite and diamonds. The super-hard diamonds were created when graphite in the meteorite experienced the intense heat and pressure of entering the Earth's atmosphere and crashing into the ground. The graphite layers would have been heated and shocked enough to create bonds between them, in much the same way as humans manufacture diamonds. The new carbon crystals were too small to test for precise hardness but they are known to be harder than normal diamonds because the researchers found them by using a diamond paste to polish a slice of the meteorite. The crystals were raised more than 10 µm above the polished surface, which meant they were harder than the diamonds in the polishing paste. The researchers had seen carbon crystals that resisted the diamond polishing in one direction before, but the new crystals were unaffected when polished in every direction. The scientists then used an array of mineralogical instruments, including microscopy, spectroscopy and energy-dispersive X-rays among others, to study the structure of the crystals. This allowed them to identify them as representing two new carbon polymorphs or diamond polytypes. One is an ultra-hard rhombohedral carbon polymorph similar to diamond, while the other is a 21R diamond polytype ultra-hard diamond. The existence of ultra-hard diamonds had been predicted decades ago, but they have never before been found in nature. The novel form consists of fused graphite sheets similar to artificial diamond. Professor Tristan Ferroir, leader of the research team from the Université de Lyon in France, said the discovery was accidental, but they had thought an examination of the meteorite would lead to new findings on the carbon system. Professor Ferroir said there is currently no way to compare the structure of the new crystals to boron nitride and lonsdaleite, the artificially manufactured ultra-hard diamonds, but the findings help scientists gain a better understanding of carbon polymorphs and give them new materials to investigate and perhaps synthesize. They also show the carbon system is more complex than previously thought. The findings on the new diamond were published in the Earth and Planetary Science Letters journal on February 15. More information:* http://dx.doi.org/10.1016/j.epsl.2009.12.015 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond
I may be wrong but seems to me the pressures of entering the atmosphere did not create the diamonds unless they were in the crust. A supernova on the other hand is a more likely source of them. cheers Steve --- On Thu, 2/4/10, starsandsco...@aol.com starsandsco...@aol.com wrote: From: starsandsco...@aol.com starsandsco...@aol.com Subject: Re: [meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond To: meteorite-list@meteoritecentral.com Date: Thursday, February 4, 2010, 2:24 AM Hi list, This is off topic (sort of) to this very interesting post but it does mention graphite and diamonds. I have shared this observation before and every time I have mentioned it I have been taken wrong! Has any else noticed how the graphite inclusions in the fossil EL3, NWA 2828, 2965, Al Haggounia 001 etc. fool an electronic diamond tester? Now this is the part I have been taken wrong on, I'm not saying I have found testable size diamonds but rather the graphite will set off an electronic diamond tester! Those testers operate on thermal conductivity. I can take my optical scopes to 2000X but that is no help in this stuff. I have tried similar inclusions in other meteorites and nothing. Is the inclusion made of nano diamonds or just a material that is as thermally conductive as diamonds? Which ever, it is interesting! Tom Phillips In a message dated 2/3/2010 6:23:57 P.M. Mountain Standard Time, baalke @zagami.jpl.nasa.gov writes: http://www.physorg.com/news184402061.html Meteorite yields carbon crystals harder than diamond by Lin Edwards physorg.com February 3, 2010 (PhysOrg.com) -- Two new types of ultra-hard carbon crystals have been found by researchers investigating the ureilite class Haverö meteorite that crashed to Earth in Finland in 1971. Ureilite meteorites are carbon-rich and known to contain graphite and diamonds. The super-hard diamonds were created when graphite in the meteorite experienced the intense heat and pressure of entering the Earth's atmosphere and crashing into the ground. The graphite layers would have been heated and shocked enough to create bonds between them, in much the same way as humans manufacture diamonds. The new carbon crystals were too small to test for precise hardness but they are known to be harder than normal diamonds because the researchers found them by using a diamond paste to polish a slice of the meteorite. The crystals were raised more than 10 µm above the polished surface, which meant they were harder than the diamonds in the polishing paste. The researchers had seen carbon crystals that resisted the diamond polishing in one direction before, but the new crystals were unaffected when polished in every direction. The scientists then used an array of mineralogical instruments, including microscopy, spectroscopy and energy-dispersive X-rays among others, to study the structure of the crystals. This allowed them to identify them as representing two new carbon polymorphs or diamond polytypes. One is an ultra-hard rhombohedral carbon polymorph similar to diamond, while the other is a 21R diamond polytype ultra-hard diamond. The existence of ultra-hard diamonds had been predicted decades ago, but they have never before been found in nature. The novel form consists of fused graphite sheets similar to artificial diamond. Professor Tristan Ferroir, leader of the research team from the Université de Lyon in France, said the discovery was accidental, but they had thought an examination of the meteorite would lead to new findings on the carbon system. Professor Ferroir said there is currently no way to compare the structure of the new crystals to boron nitride and lonsdaleite, the artificially manufactured ultra-hard diamonds, but the findings help scientists gain a better understanding of carbon polymorphs and give them new materials to investigate and perhaps synthesize. They also show the carbon system is more complex than previously thought. The findings on the new diamond were published in the Earth and Planetary Science Letters journal on February 15. More information:* http://dx.doi.org/10.1016/j.epsl.2009.12.015 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http
