Carlfriesite

Tellurium mineral
(repeating unit)CaTe4+2Te6+O8IMA symbolClf[1]Strunz classification4.JK.25Dana classification34.5.3.1Crystal systemMonoclinicCrystal classPrismatic (2/m)
(same H-M symbol)Space groupC2/cUnit cella = 12.576, b = 5.662
c = 9.994 [Å], Z = 4IdentificationColorBright yellow – buttery yellowCrystal habitAxe-head shaped crystals, botryoidal crusts or radial crystals.CleavageDistinctTenacityBrittleMohs scale hardness3.5LusterVitreousStreakPale yellowDiaphaneityTransparentSpecific gravity6.3 (measured) 5.7 (calculated)Optical propertiesBiaxial (−)Birefringenceδ = 0.208PleochroismWeak, shades of yellow2V angle80Ultraviolet fluorescenceNoneSolubilityInsolubleReferences[1][2][3][2]

Carlfriesite is a rare tellurium mineral with the formula CaTe4+2Te6+O8, or more simplified: CaTe3O8. It has a Moh's hardness of 3.5 and it occurs in various shades of yellow, ranging from bright yellow to a light buttery color. It was named after Carl Fries Jr. (1910–1965) from the U.S. Geological Survey and the Geological Institute of the National University, Mexico City, Mexico.[3][4][5] It was previously thought to have the formula H4Ca(TeO3)3, but this was proven to be incorrect.[6] It has no uses beyond being a collector's item.

Occurrence

Carlfriesite is often found in cavities in hydrothermal gold-tellurium deposits. It is found associated with cerussite, chlorargyrite, argentian gold, cesbronite, calcite, dickite, baryte, bornite, galena, hessite and tlapallite.[5] It was first identified in the Bambollita (La Oriental), Moctezuma, Municipio de Moctezuma, Sonora, Mexico. It is also found in another nearby mine, namely the Moctezuma mine.

Synthesis

Carlfriesite was found to be synthesizable by heating a mixture of CaO, Te(OH)6 and TeO2 to 150–240°C with water at the vapor pressure of the system. The resulting material was very fine-grained and colorless, consisting of aggregates of tiny carlfriesite plates. The material mostly consisted of carlfriesite, but also contained 10–15% paratellurite, as determined by X-ray diffraction.[6]

See also

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mineralienatlas
  3. ^ Barthelmy, Dave. "Carlfriesite Mineral Data". www.webmineral.com. Retrieved 2016-09-19.
  4. ^ "Carlfriesite: Carlfriesite mineral information and data". www.mindat.org. Retrieved 2016-09-19.
  5. ^ a b "Handbook of mineralogy" (PDF). Retrieved 2016-09-19.
  6. ^ a b Herta Effenberger; Josef Zemann; Helmut Mayer (1978). "Carlfriesite: crystal structure, revision of chemical formula, and synthesis" (PDF). American Mineralogist. 63. Retrieved 2016-09-19.
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Selenites, selenates, tellurites, and tellurates
Selenites 28.1
Ahlfeldite Chalcomenite Clinochalcomenite Cobaltomenite Demesmaekerite Derriksite Francisite Guilleminite Haynesite Mandarinoite Marthozite Molybdomenite Sofiite
Selenates 28.2
Olsacherite Schmiederite
Tellurites 28.3
Balyakinite Blakeite Cesbronite Chekhovichite Choloalite Cliffordite Denningite Emmonsite Eztlite Fairbankite Graemite Keystoneite Kinichilite Mackayite Moctezumite Mroseite Plumbotellurite Poughite Quetzalcoatlite Rajite Rodalquilarite Schmitterite Smirnite Sonoraite Spiroffite Teineite Winstanleyite Zemannite
Tellurates 28.4
Carlfriesite Cheremnykhite Cuzticite Dugganite Girdite Khinite Khinite-3T Kuksite Kuranakhite Montanite Oboyerite Schieffelinite Tlalocite Tlapallite Xocomecatlite Yafsoanite Yecoraite