Idrialite 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 approximate chemical formula C
22H
14.
[
Idrialite usually occurs as soft ]orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...
crystals, is usually greenish yellow to light brown in color with bluish fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...
. It is named after Idrija
Idrija (, in older sources ''Zgornja Idrija''; german: (Ober)idria, it, Idria) is a town in western Slovenia. It is the seat of the Municipality of Idrija. It is located in the traditional region of Inner Carniola and is in the Gorizia Statisti ...
, town in Slovenia
Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...
, where its occurrence was first described.[
The mineral has also been called idrialine, and ''branderz'' in ]German
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
It has also been called inflammable cinnabar due to its combustibility and association with cinnabar
Cinnabar (), or cinnabarite (), from the grc, κιννάβαρι (), is the bright scarlet to brick-red form of Mercury sulfide, mercury(II) sulfide (HgS). It is the most common source ore for refining mercury (element), elemental mercury and ...
ores in the source locality.[ A mineral found in the Skaggs Springs location of ]California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
was described in 1925 and named curtisite, but was eventually found to consist of the same compounds as idrialite, in somewhat different amounts.[ Thus curtisite is now considered to be merely a variety of idrialite.][
]
Discovery and occurrence
Idrialite was first described in 1832 for an occurrence in the Idrija region west of Ljubljana
Ljubljana (also known by other historical names) is the capital and largest city of Slovenia. It is the country's cultural, educational, economic, political and administrative center.
During antiquity, a Roman city called Emona stood in the ar ...
, northwestern Slovenia,[ mixed with ]clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...
, 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 ...
, 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 ...
and gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
associated with cinnabar
Cinnabar (), or cinnabarite (), from the grc, κιννάβαρι (), is the bright scarlet to brick-red form of Mercury sulfide, mercury(II) sulfide (HgS). It is the most common source ore for refining mercury (element), elemental mercury and ...
.[
It also occurs at the Skaggs Springs location in ]Sonoma County
Sonoma County () is a county (United States), county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its county seat and largest city is Santa Rosa, California, Santa Rosa. It is to the n ...
, in western Lake County, and in the Knoxville Mine in Napa County, California
Napa County () is a county north of San Pablo Bay located in the northern portion of the U.S. state of California. As of the 2020 census, the population was 138,019. The county seat is the City of Napa. Napa County was one of the original co ...
.[ It has also been reported from localities in ]France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, 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 ...
and Ukraine
Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...
.[
In the Skaggs Springs occurrence, the mineral occurs in a hot spring area of the ]Franciscan formation
The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula. It was named by geologist Andrew ...
, around a vent in the sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates) ...
that gave off inflammable gases. The mineral was described in 1925 and named "curtisite" after the local resident L. Curtis who called attention to it.[ The crystals are square or six sided flakes, 1 mm in diameter, yellow to ]pistachio
The pistachio (, ''Pistacia vera''), a member of the cashew family, is a small tree originating from Central Asia and the Middle East. The tree produces seeds that are widely consumed as food.
''Pistacia vera'' is often confused with other sp ...
green in transmitted light. It is associated with opaline silica, realgar
Realgar ( ), also known as "ruby sulphur" or "ruby of arsenic", is an arsenic sulfide mineral with the chemical formula α-. It is a soft, sectile mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in asso ...
(arsenic sulfide) and metacinnabarite
Metacinnabar is the cubic form of mercury sulfide (HgS). It is the high temperature form and trimorphous with cinnabar (trigonal structure) and the higher temperature hypercinnabar (hexagonal structure). It occurs with cinnabar in mercury depos ...
(mercuric sulfide), which had been deposited in that order before it.[
]
Composition and properties
The Curtisite variety is only slightly soluble in hot acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour.
Acetone is miscib ...
, amyl acetate
Amyl acetate (pentyl acetate) is an organic compound and an ester with the chemical formula CH3COO H2sub>4CH3 and the molecular weight 130.19g/mol. It is colorless and has a scent similar to bananas and apples. The compound is the condensation pr ...
, butanol
Butanol (also called butyl alcohol) is a four-carbon alcohol with a formula of C4 H9 O H, which occurs in five isomeric structures (four structural isomers), from a straight-chain primary alcohol to a branched-chain tertiary alcohol; all are a b ...
, petroleum ether
Petroleum ether is the petroleum fraction consisting of aliphatic hydrocarbons and boiling in the range 35–60 °C, and commonly used as a laboratory solvent. Despite the name, petroleum ether is not classified as an ether; the term is used ...
. The solubility is 0.5% or less in hot carbon bisulfide, carbon tetrachloride
Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVAC ...
, chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...
, diethyl ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...
, or boiling benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...
; about 1.5% in toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) at ...
, about 2.5% in xylene
In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are sub ...
, and over 10% in hot aniline
Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine
In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ...
. The material purified by repeated recrystallization melts at 360-370 C while turning very black. It sublimes giving very thin iridescent colors.[
]Raman spectroscopy
Raman spectroscopy () (named after Indian physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman sp ...
studies indicate that it may be a mixture of complex 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 ...
s including benzonaphthothiophenes (chemical formula: C16H10S) and dinaphthothiophenes (chemical formula: C20H12S).[
Curtisite and idrialite have been found to be unique complex mixtures of over 100 ]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. P ...
s (PAHs) consisting of six specific PAH structural series with each member of a series differing from the previous member by addition of another aromatic ring. The curtisite and idrialite samples contained many of the same components but in considerably different relative amounts.[ ][
The major PAH constituents of the curtisite sample were: ]picene
Picene is a hydrocarbon found in the Pitch (resin), pitchy residue obtained in the distillation of peat tar and of petroleum. This is distilled to dryness and the distillate repeatedly Recrystallization (chemistry), recrystallized from cymene. It ...
(a PAH with 5 fused benzene rings), dibenzo luorene">,hluorene, 11H-indeno henanthrene">,1-ahenanthrene, benzo henanthro[2,1-d">henanthro[2,1-dhiophene.html" ;"title=",1-d.html" ;"title="henanthro[2,1-d">henanthro[2,1-dhiophene">,1-d.html" ;"title="henanthro[2,1-d">henanthro[2,1-dhiophene, indenofluorenes, chrysene, and their methyl- and dimethyl-substituted homologues; the major components in the idrialite sample were higher-molecular-weight PAH, i.e. benzonaphthofluorenes (molecular weight 316), benzoindenofluorenes (MW 304) and benzopicene (MW 328), in addition to the compounds found in the curtisite sample.[
Curtisite is also associated with small amounts of a dark brown oil, that appears to be responsible for some of the yellow color and most of the fluorescence, and can be separated by recrystallization.][
Based on the composition, it was conjectured that the compounds were produced by medium-temperature ]pyrolysis
The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...
of organic matter, then further modified by extended equilibration at elevated temperatures in the subsurface and by recrystallization during migration.[
When distilled, it produces the mineral wax idrialin.][
]
References
[Curtisite]
page at the Mindat.org online database. Accessed on 2020-08-28.
page at the Mindat.org online database. Accessed on 2020-08-28.
[Dave Barthelmy (2012):]
Idrialite Mineral Data
. Online document at Webmineral.com. Accessed on 2020-08-28.
[F. E. Wright and E. T. Allen (1925): "Curtisite, a new organic mineral from Skaggs Springs, Sonoma County, California (abstract)" ''American Mineralogist'', volume 11, pages 67-67.]
[F. E. Wright and E. T. Allen (1930):]
Curtisite, a new organic mineral from Skaggs Springs, Sonoma County, California
. ''American Mineralogist'', volume 15, pages 169-173.
[T. A. Geissman, K. Y. Sun, and J. Murdoch (1967): "Organic minerals. Picine and chrysene as constituents of the mineral Curtisite (idrialite)". ''Experentia'', volume 23, pages 793-794.]
[Idrialite]
entry in John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, and Monte C. Nichols ():
Handbook of Mineralogy
'. Published by the Mineralogical Society of America. Accessed on 2020-08-28
[Max Blumer (1975): "Curtisite, idrialite and pendletonite, polycyclic aromatic hydrocarbon minerals: Their composition and origin" ''Chemical Geology'', volume 16, issue 4, pages 245-256. ]
[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. ]
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Organic minerals
Orthorhombic minerals
Luminescent minerals
Minerals described in 1832