< Minerals
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.

Diamonds

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.

Graphites

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.

Chaoites

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]

Lonsdaleites

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]

Fullerites

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 carbons

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 minerals

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

Carpathites

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.

Idrialites

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]

Kratochvilites

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.

Moissanite

Moissanite is native SiC. Credit: Andrew Silver.

Moissanite is native SiC.[1]

Hoelites

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]

Abelsonites

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]

Simonellites

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.

Hartites

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

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

Fichtelites

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.

Evenkites

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]

Hypotheses

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

See also

  • Carbonates
  • Carbonites
  • Carbons
  • Organic minerals
  • Siliconides

References

  1. 1 2 3 4 5 6 7 8 9 10 Willard Lincoln Roberts; George Robert Rapp Jr.; Julius Weber (1974). Encyclopedia of Minerals. New York, New York, USA: Van Nostrand Reinhold Company. pp. 121–2. ISBN 0-442-26820-3.
  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; 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. 1 2 3 4 Otakar Frank; Jan Jehlička; 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.
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