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Minerals/Carbonides

This diamond is a nearly perfectly-formed yellow diamond crystal weighing about 253.7 carats (50.74 g). Credit: Eurico Zimbres FGEL/UERJ.

Carbonides are naturally occurring minerals composed of 50 atomic percent, or more, carbon. Carbonide-like minerals with greater than 25 at % carbon are also included. This separates carbon containing minerals from carbonates which are at most 25 at % carbon.

DiamondsEdit

 
The crystal is a single octohedron with intricately stepped faces. Credit: Robert Lavinsky.

The diamond imaged on the right has been estimated to be just over 1.5 carats. It measures 5 mm on edge. Although it might seem small, it has wonderful visual impact because of the clarity and perch on matrix. Embedded perhaps 50% in the matrix, so you know it is real. What is more, you can look right through the diamond to the matrix underneath! Around the diamond is a thin white layer you sometimes see, which indicates not glue but rather an alteration in the surrounding rock due to the chemical heat of formation of the crystal and is a good indication of its origins as natural.

GraphitesEdit

 
Natural, or native element, piece of graphite has been cut from a larger piece. Credit: USGS.

Graphite is a hexagonal form of carbon that often appears as tabular crystals.

ChaoitesEdit

 
This is a geniune natural piece of chaoite at 21.60 ct. Credit: SnipView.

Chaoites are another hexagonal form of native carbon. It occurs as "thin lamellae (3-15 microns wide), alternating with graphite and perpendicular to the {0001} face of graphite."[1]

"Occurs in association with graphite, zircon, and rutile in shocked graphite gneisses from Mottingen in the Ries Crater, Germany. Also observed from the Goalpara and Dyalpur carbonaceous chondrites."[1]

LonsdaleitesEdit

 
The mineral Lonsdaleite is made from carbon with a different arrangement than diamond. Credit: payam.

"The mineral Lonsdaleite is a translucent, brownish yellow and is made from the atoms of carbon but the arrangement of these atoms is different from the arrangement of carbon atoms in a diamond. [...] The mineral is very rare and is formed naturally whenever [...] graphite containing meteorites fall on the earth and hit the surface."[2]

"Found in the Canyon Diablo and Goalpara meteorites."[1]

FulleritesEdit

Fullerite appears to be a tentative name for the mineral occurrence of buckyballs.

"By means of high-resoluton transmission electron microscopy, both C60 and C70 fullerenes have been found in a, carbon-rich Precambrian rock from Russia The fullerenes were confirmed by Fourier transform mass spectrometry with both laser desorption and thermal desorption/electron-capture methods to verify that the fullerenes were indeed present in the geological sample".[3]

Space carbonsEdit

 
This is a piece of carbon from space. Credit: Francine Loubrieu.

Apparently graphitic-like carbon particles such as shown in the image on the right have been found in space and brought back to Earth.

Organic mineralsEdit

An organic mineral appears to be a naturally occurring mineral containing one or more organic chemicals at a concentration of greater than 25 molecular %.

CarpathitesEdit

 
Radial spray of highly lustrous, canary-yellow carpathite lathes reach to 2.0 cm. Credit: Rob Lavinsky.
 
This is carpathite under ultraviolet light. Credit: Rama.

Carpathite (aka Karpatite) is a very rare organic species (C24H12).[1] It is a polycyclic aromatic hydrocarbon (PAH). This specimen is from the old Picacho Mercury Mine of California. It exhibits a radial spray of highly lustrous, canary-yellow carpathite lathes to 2.0 cm on drusy quartz. Another crossed cluster of crystals above reach 3.0 cm. It has 66.7 at % carbon.

IdrialitesEdit

 
A very rare, greenish yellow, orthorhombic, organic mineral, curtisite is a synonym for idrialite. Credit: Rob Lavinsky.

With a formula of C22H14,[1] idrialites are about 61 at % carbon.

Idrialite is "a complex natural mineral composed entirely of cata-condensed polyaromatic hydrocarbons (PAHs), usually containing a thiophenic or aliphatic five-membered ring."[4]

Idrialite "(and also curtisite) represents more complex mixtures of chain-type PAHs with molecular weights ranging from 216 to 372 amu [5]."[4]

"Some of the bands in the idrialite spectra are attributed to specific vibrational modes of thiophene or fluorene-type PAHs, especially in the region bellow 1000 cm−1. These modes at 495, 705 and 750 cm−1 along with C–H or C–H2 stretching modes around 3000 cm−1 can be then used to distinguish such groups of PAHs in complicated organic mineral mixtures like idrialite."[4]

Idrialite may include benzonaphthothiophenes (chemical formula: C16H10S).[4]

KratochvilitesEdit

Def. a "rare organic mineral [C14H10 or (C6H4)2CH2, a polymorph of fluorene], an orthorhombic hydrocarbon formed by combustion of coal or pyritic black shale deposits"[5] is called kratochvilite

Kratochvilites have about 58.3 at % carbon.

MoissaniteEdit

 
Moissanite is native SiC. Credit: Andrew Silver.

Moissanite is native SiC.[1]

HoelitesEdit

 
Yellow acicular crystals of Hoelite (picture size: 10 mm) are from Carolaschacht Mine, Freital near Dresden, Saxony, Germany. Credit: Thomas Witzke.

Hoelites are 50 at % carbon with a formula of (C6H4)2(CO)2.[1]

AbelsonitesEdit

 
The reddish abelsonite crystal is 1.8 mm long. Credit: Thomas Witzke.

Abelsonites have a chemical formula of NiC31H34N4, for 44.3 at % carbon.[1]

SimonellitesEdit

 
This is a colorless to white Simonellite on fossil wood. Credit: Thomas Witzke / Abraxas-Verlag.

Def. an "orthorhombic-dipyramidal white mineral containing carbon and hydrogen [C19H24]"[6] is called a simonellite.

Simonellites have about 44.2 at % carbon.

HartitesEdit

 
Hartite locality is Oberhart near Gloggnitz, Austria. Credit: Ra'ike.

Hartites have about 37 at % carbon with a formula of C20H34.[1]

FichtelitesEdit

Def. a "rare white monoclinic organic mineral, [7-isopropyl-1,4a-dimethyl-dodecahydro-1H-phenanthrene (C19H34)],[7] found in fossilized wood"[8] is called a fichtelite.

Also, occurs in "fossilized pine wood from a peat bog; in organic-rich modern marine sediment."[9]

Fichtelites have about 35.8 at % carbon.

EvenkitesEdit

 
Aggregates of colourless evenkite in vugs of altered andesite, where the evenkite was confirmed by PXRD. Credit: Martin Stevko.

Evenkite has about 32.4 at % carbon in its formula: (CH3)2(CH2)22.[1]

HypothesesEdit

  1. The easiest resource for specific elements is as a native element mineral.

See alsoEdit

ReferencesEdit

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Willard Lincoln Roberts, George Robert Rapp, Jr., and Julius Weber (1974). Encyclopedia of Minerals. 450 West 33rd Street, New York, New York 10001 USA: Van Nostrand Reinhold Company. pp. 121–2. ISBN 0-442-26820-3. |access-date= requires |url= (help)CS1 maint: Multiple names: authors list (link)
  2. payam (30 July 2013). Top 10 Hardest Material in the world. Help Tips. Retrieved 2015-07-30.
  3. Peter R. Buseck, Semeon J. Tsipursky, and Robert Hettich (10 July 1992). "Fullerenes from the Geological Environment". Science 257 (5067): 215-7. doi:10.1126/science.257.5067.215. http://www.sciencemag.org/content/257/5067/215. Retrieved 2015-07-30. 
  4. 4.0 4.1 4.2 4.3 Otakar Frank, Jan Jehlička and Howell G.M. Edwards (15 December 2007). "Raman spectroscopy as tool for the characterization of thio-polyaromatic hydrocarbons in organic minerals". Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 68 (4): 1065–9. doi:10.1016/j.saa.2006.12.033. http://www.sciencedirect.com/science/article/pii/S1386142506007621. Retrieved 2015-11-02. 
  5. Equinox (27 October 2008). kratochvilite. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2015-01-09.
  6. Equinox (4 September 2011). simonellite. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2015-01-09.
  7. SemperBlotto (15 March 2014). fichtelite. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2015-01-09.
  8. Equinox (28 September 2010). fichtelite. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2015-01-09.
  9. R. Ruff (2005). Fichtelite (PDF). Mineral Data Publishing. Retrieved 2015-01-09.

External linksEdit