{{Infobox mineral
| name        = '''Carpathite'''
| category    = [[Organic mineral]]
| boxwidth    = 
| boxbgcolor  = 
| image       = Carpathite-258272.jpg
| imagesize   = 260px
| caption     = Carpathite from [[New Idria District]], California USA
| formula     = C<sub>24</sub>H<sub>12</sub>
| molweight   = 
| strunz      = 10.BA.30
| system      = [[Monoclinic]] 
| class       = Prismatic (2/m) <br/><small>(same [[H-M symbol]])</small>
| symmetry    = ''P2''<sub>1</sub>/c, ''P2''<sub>1</sub>/n, ''C''<sub>2</sub>''h''<sup>4</sup>.<ref name=murd1967/>
| unit cell   = a = 1625 pm, b = 463.8 pm, c = 1042 pm; β = 111°10';<ref name=murd1967/><!--a = 1003 pm, b = 469 pm, <br/>c = 1601 pm; β = 111°;--> Z = 2
| color       = Yellow, yellowish brown on exposure
| habit       = Acicular to thin tabular in bladed groups and fibrous radiating aggregates
| twinning    = 
| cleavage    = Perfect on [001], [100] and [{{overline|2}}01]
| fracture    = Splintery
| tenacity    = Flexible, nearly plastic
| mohs        = 1.5
| luster      = Vitreous - adamantine
| refractive  = n<sub>α</sub> = 1.760 - 1.780 n<sub>β</sub> = 1.780 - 1.982 n<sub>γ</sub> = 2.050 - 2.150
| opticalprop = Biaxial (+/-)
| birefringence = δ = 0.290 - 0.370
| pleochroism = 
| streak      = Yellow white
| gravity     = 1.35
| density     = 
| melt        = 432.8 °C <ref name=echi2007/> 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = Transparent
| other       = Fluorescent - electric blue to blue-green
| references  = <ref name=minatlas/><ref name=mindat/><ref name=webmin/><ref name=HBM/>
}}
'''Carpathite''' is a very rare hydrocarbon mineral, consisting of exceptionally pure [[coronene]] (C<sub>24</sub>H<sub>12</sub>), a [[polycyclic aromatic hydrocarbon]].<ref name=blum1975/><ref name=wise1986/> The name has been spelled '''karpatite'''<ref name=echi2007/> and the mineral was improperly renamed '''pendletonite'''.<ref name=murd1967/>

==Discovery==
The mineral was first described in 1955 for an occurrence in [[Transcarpathian Oblast]], [[Ukraine]]. It was named for the [[Carpathian Mountains]].<ref name=mindat/>

In 1967, unaware of the earlier descripton, [[Joseph Murdoch]] analyzed and described a specimen from the [[Picacho Peak]] area of [[San Benito County, California]] and named it "pendletonite".<ref name=murd1967/>

==Structure==
Carpathite has the same crystal structure of pure coronene.  The molecules are planar and lie in two sets with roughly perpendicular orientations.  Molecules in the same set are parallel and partially offset, with planes 0.3463 [[nanometre|nm]] apart.  That is slightly larger than the inter-layer distance of [[graphite]] layers (0.335 nm), and much larger than the C-C bond lengths within the molecule (about 0.14 nm).  This "corrugated layer" structure is highly resistant to intercalation, which apparently explains the purity of the mineral.<ref name=echi2007/>

==Occurrence==
In the Ukraine discovery location, it occurs at the contact zone of a [[diorite]] intrusive into [[argillite]] within cavities, and is associated with [[idrialite]], [[amorphous]] organic material, [[calcite]], [[barite]], [[quartz]], [[cinnabar]], and [[metacinnabar]].<ref name=HBM/>. It has also been been reported in the [[Presov Region]] of the [[Slovak Republic]]<ref name=mindat/> and in the [[Kamchatka Oblast]] in Russia.<ref name=mindat/>

In the [[California]] location, it occurs in centimeter-size veins, associated (and somewhat contemporaneous) with [[quartz]] and cinnabar, in a silicified matrix. Crystals are up to 10 × 1 × 1 [[millimetre|mm]].<ref name=murd1967/> Carbon [[isotope]] ratios and the morphology of the deposit indicate that the coronene was produced from organic matter in oceanic sediment, thermally decomposed, purified through [[hydrothermal]] transportation and chemical reactions, and deposition below 250 °C, after the other minerals in the intrusion.<ref name=echi2007/>

==References==
<references>

<ref name=minatlas>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Carpathite Mineralienatlas]</ref>

<ref name=mindat>[http://www.mindat.org/min-2162.html Mindat with location data]</ref>

<ref name=webmin>[http://www.webmineral.com/data/Karpatite.shtml Webmineral data]</ref>

<ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/karpatite.pdf Handbook of Mineralogy]</ref>

<ref name=murd1967>Joseph Murdoch and Theodore A. Geissman (1967): "[https://watermark.silverchair.com/am-1967-611.pdf Pendletonite, a new hydrocarbon mineral from California]". ''American Mineralogist'', volume 52, issues 5-6, pages 611–616. Quote: "''Mr. Forrest Cureton, who sent in the specimens, has asked that the mineral, if it turned out to be new, be named after Mr. Norman H. Pendleton, of Santa Cruz, California, who was apparently the first to suspect that the crystals were not [[valentinite]]''"<!--No DOI?--></ref>

<ref name=wise1986>Stephen A. Wise, Robert M. Campbell, W. Raymond West, Milton L. Lee, Keith D. Bartle (1986): "Characterization of polycyclic aromatic hydrocarbon minerals curtisite, idrialite and pendletonite using high-performance liquid chromatography, gas chromatography, mass spectrometry and nuclear magnetic resonance spectroscopy". ''Chemical Geology'', volume 54, issues 3–4, pages 339-357. {{doi|10.1016/0009-2541(86)90148-8}}</ref>

<ref name=echi2007>Takuya Echigo, Mitsuyoshi Kimata, and Teruyuki Maruoka (2007): "Crystal-chemical and carbon-isotopic characteristics of karpatite (C<sub>24</sub>H<sub>12</sub>) from the Picacho Peak Area, San Benito County, California: Evidences for the hydrothermal formation". ''American Mineralogist'', volume 92, issues 8-9, pages 1262–1269.
{{doi|10.2138/am.2007.2509}}</ref>

<ref name=blum1975>Max Blumer (1975): "Curtisite, idrialite and pendletonite, polycyclic aromatic hydrocarbon minerals: Their composition and origin" ''Chemical Geology'', volume 16, issue 4, pages 245-256. {{doi|10.1016/0009-2541(75)90064-9}}</ref>

</references>

{{Commons category|Carpathite|position=left}}

[[Category:Organic minerals]]
[[Category:Monoclinic minerals]]

{{mineral-stub}}