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GeneralIs this "aluminum" possibly real?
7th Jan 2005 22:42 UTCBob
I looked around for rules and couldn't find any, so I hope that I'm not posting anything wrong here.
I am watching an auction on eBay, and wonder if you experts could tell me if this is a legit mineral specimen or not. I've never seen anything like it, and can't find any reference to it in any of my books.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6502371838
The listing leads one to believe that this is a specimen of native aluminum.
Is that possible? Do you think this may be slag from a smelter or the like?
I would appreciate any thoughts you may have on this piece. It sure is an interesting looking item, but....
Also, just what does one have to do to enter the chat area?
Thank you for any replies. Hope that I didn't break any rules by posting an auction link.
Bob
8th Jan 2005 00:11 UTCAlfredo
This is why many of us prefer to buy our minerals at shows, so we can pick the rocks up, look at all sides with a loupe, compare other specimens from the same locality, see whether the seller is grinning insanely, etc, etc....
The specimen in question has a shape remarkably similar to synthetic specimens, but who knows, maybe this is a case of life imitating art, but I won't be bidding against you, Bob!
8th Jan 2005 01:40 UTCJim Ferraiolo
The native aluminum discovered in the Lianhuashan tungsten deposit, Guangdong.
He-Shuahgmei; Cao-Fenyuan; Liu-Yanzhong
Dizhi yu Kantan = Geology and Prospecting. 26; 9, Pages 32-34. 1990.
Abstract: Native aluminum was discovered in quartz dioritic porphyrite and altered quartz sandstone in the Lianhuashan tungsten mining district. It has an irregular grain shape, usually 0.02-0.04mm in size and white in colour, and occurs as an impregnation ore in gangue minerals.
Discovery of native aluminum in the oxidation zone in Getang, Anlong County, Guizhou Province.
Jiang-Xinshun; Li-Wenkang; Zhang-Shuxin; Meng-Fanyi
Bulletin of the Chinese Academy of Geological Sciences. 11; Pages 79-86. 1985.
Abstract: Native aluminum was discovered in the jarositized quartzitic rock of replacement origin at Getang, Anlong County, Guizhou Province. The bulk of the native aluminum occurs in cracks in and along boundaries of jarosite, and only a small amount is present in and along the grain boundaries of quartz. It is frequently associated with native copper and sulfur which have replaced jarosite. Electron-probe analysis shows that it contains 97.811% of aluminium, and electron diffraction and X-ray powder method indicate that a (sub o) is 4.0507Aa. So it is considered as native aluminum.
The size listed for the first occurrence above is probably the largest I've seen, and these are irregular grains, not crystal groups.
8th Jan 2005 04:39 UTCAlfredo
8th Jan 2005 08:16 UTCMatt
As a PhD chemist with 25 years experience I would argue that in spite of these reports aluminium will never, never, never, ever occur free in nature as the native metal. It is not only a case of reduction from its ores, but also in the electronegativity scale aluminum is the 6th most reactive metal known. Consequently left out in the open it will very rapidly react with oxygen, water or anyhting else for that matter, to become an aluminium compound and thus not the native metal. You may thin, oh I've had an aluminium cooking pot for years, but if you look carefully the surface is always dull and not metallic, the reason is that the surface is coated by a protective layer of aluminium oxide. Scrape that away and the bright aluminium beneath will tarnish again in a matter of hours. Anyway, thats my penny's worth.
Matt
8th Jan 2005 13:30 UTCMaurice
Well I'm afraid you are wrong here. Native aluminum DOES occur in nature. Nature provides many extreme environments. IThere are at least ten valid localities of native aluminium in Russia alone. The only one I have personally visited in the Karymsky volcano. In the 1996 Akademia Nauk volcano eruption at the foot of Karymsky volcano pumice was produced. Inside the pumice are microscopic inclusions of cordierite, glass and sulfides. native aluminium is one of the minerals found here.
Other types of localities include ultrabasic intrusions such as the Tsepochechnyi intrusion in Yakutia.
As for the thin layer of oxides on your pots and pans. That is true, but does not imply that there is no aluminum underneath! Same with the natural stuff it is shielded from the atmosphere by other minerals.
Nevertheless such large samples as the one on ebay looks very synthethic to me.
Cheers,
Maurice
8th Jan 2005 15:27 UTCJolyon
This seller seems to sell other wildly misidentified stuff, for example:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6501210405&ssPageName=MERC_VI_RSCC_Pr4_PcY_BIN_Stores
is shown as a 'stannite gem crystal cluster', with green translucent Stannite crystals! (for those who don't know, Stannite is a metallic mineral)
So I would treat their 'Aluminium' with great suspicion!
8th Jan 2005 17:54 UTCDave
I saw this offering a couple days back, having worked with metals all my life as a toolmaker. the rockhound is always curious. Native AL does exist, but I've never read about anything much bigger than sand grain size.
Any claims made on Ebay become suspect, and any materials coming out of China doubly so.
8th Jan 2005 18:55 UTCEverett
As far as chat do you get a gray screen? If you do you must wait for the java to load. If you dont get a gray screen (XP) computers sometimes you have to go download sun java found here http://java.sun.com/
Hope this helps.
A group of us chats every day around 8 Michigan time......
E
8th Jan 2005 19:11 UTCRay
8th Jan 2005 19:20 UTCMaurice
I'm caution about any rare native element (Ti, Si, In, Ta etc) . Especially in the mineral market. The same goes for the expensive PGM minerals, where you get an analysed 0.1mm grain with five rare minerals and an SEM picture for $300. Too much money for something I can not check for myelf!
I do happen to have a Karymsky native Aluminium, but I got it personally from a Kamchatkan volcanologist while I was there. I saw the analyses and took their word for it. Then again it was a free gift. :-)
Cheers,
Maurice
8th Jan 2005 21:58 UTCAlfredo
Nature can easily reduce Fe minerals to native iron with just heat and carbon, which is why native iron is not a rare mineral, but that isn't possible with aluminum.
8th Jan 2005 22:18 UTCian jones
As Alfredo wisely points out - Caveat emptor.
9th Jan 2005 00:07 UTCBob
Caveat emptor indeed!
12th Jan 2005 20:11 UTCDon Webb
12th Jan 2005 21:28 UTCAlfredo
13th Jan 2005 09:22 UTCChris Popham
That aside the aluminium is very interesting to look at natural or otherwise but I'm not sure it's $700 interesting.
Chris
13th Jan 2005 23:04 UTCandy christy
1. Although it is true that the electrode potential of coating-free Al metal is very positive, and that the formation of corundum from Al and oxygen is very exothermic, it should be borne in mind that the partial pressure of oxygen in deep-sourced igneous materials starts VERY VERY low.
2. At high temperatures, Al is not only volatile itself, but also (under reducing conditions) forms a gaseous suboxide Al2O. Theformation of the latter is a counterindication for using alumina as a ceramic material under reducing conditions at high temperature, since the Al2O3 can gradually become weak and porous as Al2O evaporates out from it.
3. The high entropy of gaseous phases stabilises them relatively at high T, which therefore makes low oxidation states (0 and +1) of aluminium more favourable relative to Al3+ in corundum.
I suspect that vapour transport of Al and Al2O followed by reverse disproportionation of the latter on cooling is important in producing the metal at Tolbachik.
I agree completely that if any of this material was left on a mine dump for a few centuries, there would be little native Al remaining. However, the host samples for Al are all, as far as I know, recently obtained drillcore or fresh fumarole deposits.
Room-temperature thermodynamic data should be used with great caution in predicting the occurrence or not of mineral phases, which may have formed under very different equilibrium or disequilibrium conditions, and persist only through slow kinetics of re-equilibration. Just look at the carbon polymorphs:
graphite is the stablest form of pure C at ambient , and is common, as predicted.
diamond should not occur in the crust, but does, because it is possible to get it to the surface and cool it fast enough to prevent inversion to graphite.
lonsdaleite, chaoite (if real), and buckyballs do not have stability fields, are ALWAYS metastable, but nevertheless occur in shocked or otherwise disequilibrated material.
And all of these forms ought to burn to CO2 in a 20% oxygen atmosphere, but the kinetics is slow unless you help them!
19th Jan 2005 07:36 UTCRock Currier
Al, A native metallic element.
Aluminum has now been found in several localities in Russia and elsewhere. It has been found in diatremes in Kazakhstan and a skarn deposit at Taror, Tajikistan and in epithermal veins at Nikitovka Mercury deposit, Ukraine. Also found in a lunar rock. Initially there were many in Russia and elsewhere who felt that native aluminum was reported in error. Even the late and highly venerated Michael Fleischer commented “This seems extremely improbable from thermodynamic considerations.” Translating this into the common vernacular it means “No fu----- way!” Dmitry Belakovsky of Moscow thought he had discovered native aluminum in some charoite samples he was working on. It turned out however that the aluminum was from the aluminum foil that the miners had used to wrap the explosives they were using when blasting the charoite out of the deposit. This and other reasons made it difficult for many researchers to believe that native aluminum had actually been discovered. Dimitry assures me however that he has seen some specimens of aluminum in matrix that are certainly authentic.
1 American Mineralogist, Vol. 65, p205, 1980.
Russia
Southern Ural Mountains, Orenburg Oblast, Kumak Deposit. Material was found in quartz veins. The best specimen was a 3 cm piece of gray white quartz with a thin sheet of native aluminum measuring about 5 mm across.1 The specimen is in the Fersman Museum in Moscow.
1 Dmitry Belakovsky, personal communication 2002.
19th Jan 2005 07:37 UTCRock Currier
*Aluminum Rare species collections.
Al, A native metallic element.
Aluminum has now been found in several localities in Russia and elsewhere. It has been found in diatremes in Kazakhstan and a skarn deposit at Taror, Tajikistan and in epithermal veins at Nikitovka Mercury deposit, Ukraine. Also found in a lunar rock. Initially there were many in Russia and elsewhere who felt that native aluminum was reported in error. Even the late and highly venerated Michael Fleischer commented “This seems extremely improbable from thermodynamic considerations.” Translating this into the common vernacular it means “No fu----- way!” Dmitry Belakovsky of Moscow thought he had discovered native aluminum in some charoite samples he was working on. It turned out however that the aluminum was from the aluminum foil that the miners had used to wrap the explosives they were using when blasting the charoite out of the deposit. This and other reasons made it difficult for many researchers to believe that native aluminum had actually been discovered. Dimitry assures me however that he has seen some specimens of aluminum in matrix that are certainly authentic.
1 American Mineralogist, Vol. 65, p205, 1980.
Russia
Southern Ural Mountains, Orenburg Oblast, Kumak Deposit. Material was found in quartz veins. The best specimen was a 3 cm piece of gray white quartz with a thin sheet of native aluminum measuring about 5 mm across.1 The specimen is in the Fersman Museum in Moscow.
1 Dmitry Belakovsky, personal communication 2002.
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Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 19, 2024 21:11:05