Evenkite is a rare

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

mineral with formula C₂₄H₅₀; specifically, H₃C–(CH₂)₂₂–CH₃, the

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which ...

''n''-

tetracosane Tetracosane, also called ''tetrakosane'', is an alkane hydrocarbon with the structural formula H(CH2)24H. As with other alkanes, its name is derived from Greek for the number of carbon atoms, 24, in the molecule. It has 14,490,245 constitutional ...

. It occurs as very soft (

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

1) transparent crystals, colorless to yellow, with a waxy luster. The softness is a characteristic of crystalline long-chain alkanes, which are the main constituents of

paraffin wax Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to m ...

. Evenkite one of very few minerals that consist of crystalline hydrocarbons, which include

carpathite Carpathite is a very rare hydrocarbon mineral, consisting of exceptionally pure coronene (C24H12), a polycyclic aromatic hydrocarbon. The name has been spelled karpatite and the mineral was improperly renamed pendletonite. Discovery The mineral wa ...

(pure crystalline

coronene Coronene (also known as superbenzene and cyclobenzene) is a polycyclic aromatic hydrocarbon (PAH) comprising seven peri-fused benzene rings. Its chemical formula is . It is a yellow material that dissolves in common solvents including benzene, tol ...

, a

polyaromatic hydrocarbon A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...

). It is also one of the few non-porous minerals that floats on water. It has been claimed to be the same as

hatchettite Hatchettite (also mountain tallow, mineral tallow, mineral adipocire, or adipocerite) is a mineral hydrocarbon. It has been claimed to be the same as evenkite. Characteristics Hatchettite occurs in the coal measures of Belgium and elsewhere, occ ...

History and geologic occurrence

Evenkite was first described in 1953 by A. V. Shropyshev, as found in the Khavokiperskiye deposit, Lower Tunguska River,

Evenkiysky District Evenkiysky District (russian: Эвенки́йский райо́н), or Evenkia (russian: Эвенкия),According to Article 2.4 of the Charter of Evenkiysky Municipal District, the names "Evenkiysky Municipal District" and "Evenkia" have e ...

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

, where it occurs inside

geode A geode (; ) is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the fill ...

s and

vug A vug, vugh, or vugg ( ) is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity (folding and faulting) are partially filled by quartz, ...

s in a

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

welded tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

. It was named after the district. It has also been reported from the

Hautes-Alpes Hautes-Alpes (; oc, Auts Aups; en, Upper Alps) is a department in the Provence-Alpes-Côte d'Azur region of Southeastern France. It is located in the heart of the French Alps, after which it is named. Hautes-Alpes had a population of 141,220 ...

region in France and the Slanské and

Vihorlat Vihorlat Mountains ( sk, Vihorlatské vrchy; ua, Вигорлат, ''Vyhorliat'') or colloquially Vihorlat is a volcanic mountain range in eastern Slovakia and western Ukraine. A part of the range is listed as a World Heritage Site. Etymolog ...

mountains of

Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...

. Evenkite appears as flaky wax partials on top of the quartz crystals. Associated minerals include quartz,

chalcedony Chalcedony ( , or ) is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. ...

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

pyrrhotite Pyrrhotite is an iron sulfide mineral with the formula Fe(1-x)S (x = 0 to 0.2). It is a nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is ...

sphalerite Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimen ...

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mo ...

and

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

. Evenkite was the last part of the geode to form. It is believed to have resulted from thermal cracking of the organic matter (manly marine plants) that where trapped in the septarian concretions during the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

burial, as the buried sediments were subjected to high pressure and temperatures. The

French Alps The French Alps are the portions of the Alps mountain range that stand within France, located in the Auvergne-Rhône-Alpes and Provence-Alpes-Côte d'Azur regions. While some of the ranges of the French Alps are entirely in France, others, such as ...

region received a lot of geological uplift after the Jurassic burial.

References

Skropyshev, A.V. "On Paraffin from a Base Metal Vein". Doklady Acad, 1953, P.717-719. Spangenberg, J.E. and Meisser, N. "Geochemistry of the organic mineral evenkite in septarian concretions in the Oxfordian marls of the French Alps". Mineralogical Magazine, 1998, p.1436-1437. J. E. Spangenberg and N. Meisser (2000): ""Hatchettite and Evenkite - two mineral names for the same natural crystalline paraffinic vax sotope ratio study. Paper EDB-00:118740 ''Abstracts of the 5th Isotope Workshop of European Society for Isotope Research'', pages 188-191. Pilonen, P.C. and Ercit, T.S. "New Mineral Names". American Mineralogist, 2005, p.1466-1469. Platonova, N.V. and Kotel'nikova, E.N. "Synthesis of Organic Mineral Evenkite". Geology of Ore Deposits, 2006, p.87-91. Kotel'nikova, E.N., Platonova, N.V., and Filatov, G.M. "Identification of Biogenic Paraffins and Their Thermal Phase Transitions". Geology of Ore Deposits, 2006, p.607-709. Jechlicka, J., Villar, S., and Edwards, G.M. "Raman spectroscopy of natural accumulated paraffins from rocks: Evenkite, ozokerite, and hatchtine". Spectrochimica Act, 2007, p.1143-1148. Takuya Echigo, Mitsuyoshi Kimata, and Teruyuki Maruoka (2007): "Crystal-chemical and carbon-isotopic characteristics of karpatite (C₂₄H₁₂) from the Picacho Peak Area, San Benito County, California: Evidences for the hydrothermal formation". ''American Mineralogist'', volume 92, issues 8-9, pages 1262–1269. Note: the name should be spelled "carpathite". {{Commons category, Evenkite, position=left Organic minerals Orthorhombic minerals Minerals in space group 57 Luminescent minerals Minerals described in 1953

History and geologic occurrence

See also

References