Idrialite

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Idrialite
2V angle
84°
Ultraviolet fluorescenceShort UV=blue, orange, yellow, green white
References[2][3][4]

Idrialite is a rare hydrocarbon mineral with approximate chemical formula C22H14.[2][3][4]

Idrialite usually occurs as soft

orthorhombic crystals, is usually greenish yellow to light brown in color with bluish fluorescence. It is named after Idrija, town in Slovenia, where its occurrence was first described.[4]

The mineral has also been called idrialine, and branderz in German It has also been called inflammable cinnabar due to its combustibility and association with cinnabar ores in the source locality.[5] A mineral found in the Skaggs Springs location of California was described in 1925 and named curtisite, but was eventually found to consist of the same compounds as idrialite, in somewhat different amounts.[6][7] Thus curtisite is now considered to be merely a variety of idrialite.[8]

Discovery and occurrence

Idrialite was first described in 1832 for an occurrence in the Idrija region west of

clay, pyrite, quartz and gypsum associated with cinnabar.[2]

It also occurs at the Skaggs Springs location in Sonoma County, in western Lake County, and in the Knoxville Mine in Napa County, California.[2] It has also been reported from localities in France, Slovakia and Ukraine.[4]

In the Skaggs Springs occurrence, the mineral occurs in a hot spring area of the

metacinnabarite (mercuric sulfide), which had been deposited in that order before it.[10]

Composition and properties

The Curtisite variety is only slightly soluble in hot

carbon bisulfide, carbon tetrachloride, chloroform, diethyl ether, or boiling benzene; about 1.5% in toluene, about 2.5% in xylene, and over 10% in hot aniline. The material purified by repeated recrystallization melts at 360-370 C while turning very black. It sublimes giving very thin iridescent colors.[10]

Raman spectroscopy studies indicate that it may be a mixture of complex hydrocarbons including benzonaphthothiophenes (chemical formula: C16H10S) and dinaphthothiophenes (chemical formula: C20H12S).[11]

Curtisite and idrialite have been found to be unique complex mixtures of over 100

polyaromatic hydrocarbons (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.[6] [12]

The major PAH constituents of the curtisite sample were:

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.[6]

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.[10]

Based on the composition, it was conjectured that the compounds were produced by medium-temperature pyrolysis of organic matter, then further modified by extended equilibration at elevated temperatures in the subsurface and by recrystallization during migration.[7]

When distilled, it produces the mineral wax idrialin.[13][14]

References

  1. S2CID 235729616
    .
  2. ^ a b c d "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
  3. ^ a b Dave Barthelmy (2012): "Idrialite Mineral Data". Online document at Webmineral.com. Accessed on 2020-08-28.
  4. ^ a b c d e "Idrialite" page at the Mindat.org online database. Accessed on 2020-08-28.
  5. ^ Egleston, Thomas (1889). Catalogue of Minerals and Synonyms. U.S. Government Printing Office. p. 83.
  6. ^
    doi:10.1016/0009-2541(86)90148-8
  7. ^
    doi:10.1016/0009-2541(75)90064-9
  8. ^ "Curtisite" page at the Mindat.org online database. Accessed on 2020-08-28.
  9. ^ 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.
  10. ^ a b c d 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.
  11. PMID 17307383
    .
  12. ^ 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.
  13. ^ Thomson, Thomas (1838). Chemistry of Organic Bodies: Vegetables. Maclachlan & Stewart. p. 748.
  14. ^ Goldschmidt, G. (1879). Watts, Henry (ed.). Journal of the Chemical Society. The Chemical Society of Great Britain. p. 167.
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