Mixite

Mixite

Turquoise-blue mixite, Laurium, Greece. Size: 6.8 x 5.0 x 3.6 cm.
General
Category Arsenate mineral
Formula
(repeating unit)		 BiCu6(AsO4)3(OH)6·3(H2O)
Strunz classification 8.DL.15
Crystal system Hexagonal
Crystal class Dipyramidal (6/m)
H-M symbol: (6/m)
Space group P63/m
Unit cell a = 13.646(2) Å,
c = 5.920(1) Å; Z = 2
Identification
Color Blue to emerald-green, pale green, white
Crystal habit Acicular crystals often in radial clusters
Fracture Uneven
Mohs scale hardness 3-4
Luster Vitreous
Streak Pale green
Diaphaneity Transparent to translucent
Specific gravity 3.79-3.83
Optical properties Uniaxial (+)
Refractive index nω = 1.743 - 1.749 nε = 1.810 - 1.830
Birefringence δ = 0.067
Pleochroism O = colorless, E = bright green
References [1][2][3]

Mixite is a rare copper bismuth arsenate mineral with formula: BiCu6(AsO4)3(OH)6·3(H2O). It crystallizes in the hexagonal crystal system typically occurring as radiating acicular prisms and massive encrustations. The color varies from white to various shades of green and blue. It has a Mohs hardness of 3.5 to 4 and a specific gravity of 3.8. It has an uneven fracture and a brilliant to adamantine luster.

It occurs as a secondary mineral in the oxidized zones of copper deposits. Associated minerals include: bismutite, smaltite, native bismuth, atelestite, erythrite, malachite and barite.[1]

It was discovered in 1879 near J´achymov, Czech Republic by mine engineer Anton Mixa.[4] Mixite has also been found in Argentina,[5] Australia,[6] Austria,[7] France,[8] Germany,[9] Greece,[10] Hungary,[11] Italy,[12] Japan,[13] Mexico,[14] Namibia,[15] Poland,[16] Spain,[17] Switzerland,[18] the United Kingdom,[19] and the United States.[20]

Mixite is the namesake member of the mixite mineral group, which has the general chemical formula Cu2+6A(TO4)3(OH)6·3H2O, where A is a REE, Al, Ca, Pb, or Bi, and T is P or As. In addition to mixite, this mineral group contains the isostructural minerals agardite-(Y),[21][22] agardite-(Ce),[23] agardite-(Nd),[24] agardite-(La),[25] calciopetersite,[26] goudeyite,[27] petersite-(Ce),[28] petersite-(Y),[22][29] plumboagardite,[30] and zálesíite.[31]

References

  1. 1 2 Mineral data publishing PDF
  2. ↑ Mindat data with locations
  3. ↑ Webmineral data
  4. ↑ Schrauf A (1880) Ueber Arsenate von Joachimsthal. 1. Mixit, ein neues Kupferwismuthhydroarsenat, Zeitschrift für Krystallographie und Mineralogie 4, 277-285
  5. ↑ Lapis 8(4), 25 (1983).
  6. ↑ Kolitsch, U. and Elliott, P. (1999): Mineralogy of the Mount Malvern Mine near Clarendon, South Australia. Australian J. Mineral. 5, 3-17.
  7. ↑ G. Blass, A. Pichler: Carinthia II 191./111.: 43-55 (2001); Kolitsch,
  8. ↑ Wittern, Journée: "Mineralien finden in den Vogesen", von Loga (Cologne), 1997.
  9. ↑ Aufschluss 1986(11), 370ff.
  10. ↑ Voudouris, P. & Economou-Eliopoulus, M. (2003): Mineralogy and chemistry of Cu-rich ores from the Kamariza carbonate-hosted deposit (Lavrion), Greece. In: Eliopoulos et al. (Eds.): Mineral Exploration and Sustainable Development. Millpress, Rotterdam, 1039-1042.
  11. ↑ Geoda 2012/I.
  12. ↑ Piccoli, G.C. (2002): Minerali delle Alpi Marittime e Cozie. Provincia di Cuneo. Amici del Museo "F. Eusebio", Ed., Alba, 366 pp.; Piccoli, G. C., Maletto, G., Bosio, P., & Lombardo, B. (2007). Minerali del Piemonte e della Valle d'Aosta. Associazione Amici del Museo F. Eusebio - Alba, 607 pag.
  13. ↑ Matsubara et al (1992) Ganseki-Koubutsu-Koshogaku Zasshi, 87, 147-148.
  14. ↑ Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 944.
  15. ↑ Gebhard, G. (1999): Tsumeb II. A Unique Mineral Locality. GG Publishing, Grossenseifen, Germany
  16. ↑ Domańska, J.: Rędziny. Otoczak, nr. 29, p. 38-52.
  17. ↑ VIÑALS, J., CALVO, M., and MARTÍ, J. (2004): Parnauita, paratacamita y otros minerales secundarios de Cerro Minado, Almería. Revista de Minerales, 2, 5, 47-49.(in Spanish). Versions simultaneously published in Catalan (Mineralogistes de Catalunya) and in English version (Mineral Up)
  18. ↑ Ansermet, S. (2012): Mines et minéraux du Valais - II. Anniviers et Tourtemagne. With contributions by N. Meisser, Ed. Porte-plumes (Ayer).
  19. ↑ Golley, P., and Williams, R. (1995): Cornish Mineral Reference Manual. Endsleigh Publications (Truro), 104 pp.
  20. ↑ Grant, Raymond W., Bideaux, R.A., and Williams, S.A. (2006) Minerals Added to the Arizona List 1995-2005: 6.
  21. ↑ Dietrich J E, Orliac M, Permingeat F (1969) L’agardite, une nouvelle espèce minérale, et le problème du chlorotile, Bulletin de la Société Française de Minéralogie et de Cristallographie 92, 420-434
  22. 1 2 Nickel E H, Mandarino J A (1987) Procedures involving the IMA Commission on New Minerals and Mineral Names and guidelines on mineral nomenclature, American Mineralogist 72, 1031-1042
  23. ↑ Walenta K, Theye T (2004) Agardite-(Ce) of the Clara mine in the central Black Forest, Aufschluss 55, 17–23
  24. ↑ Pekov I V, Chukanov N V, Zadov A E, Voudouris P, Magganas A, Katerinopoulos A (2011) Agardite-(Nd), NdCu6(AsO4)3(OH)6·3H2O, from the Hilarion Mine, Lavrion, Greece: mineral description and chemical relations with other members of the agardite-zálesíite solid-solution system, Journal of Geosciences 57, 249-255
  25. ↑ Fehr T, Hochleitner R (1984) Agardite-La. Ein neues mineral von Lavrion, Griechenland, Lapis 9, 22-37
  26. ↑ Sejkora J, Novotný P, Novák M, Šrein V, Berlepsch P (2005) Calciopetersite from Domašov nad Bystricí, Northern Moravia, Czech Republic, a new mineral species of the mixite group, The Canadian Mineralogist 43, 1393-1400
  27. ↑ Wise W S (1978) Parnauite and goudeyite, two new copper arsenate minerals from the Majuba Hill Mine, Pershing County, Nevada, American Mineralogist 63, 704-708
  28. ↑ Williams P A, Hatert F, Pasero M, Mills S J (2014) IMA Commission on new minerals, nomenclature and classification (CNMNC) Newsletter 20. New minerals and nomenclature modifications approved in 2014. Mineralogical Magazine 78, 549-558
  29. ↑ Peacor D R, Dunn P J (1982) Petersite, a REE and phosphate analog of mixite, American Mineralogist 67, 1039-1042
  30. ↑ Walenta K, Theye T (2005) Plumboagardite, a new mineral of the mixite group from an occurrence in the Southern Black Forest, Neues Jahrbuch für Mineralogie, Abhandlungen 181, 219-224
  31. ↑ Sejkora J, Rídkošil T, Šrein V (1999) Zálesíite, a new mineral of the mixite group, from Zálesí, Rychlebské hory Mts., Czech Republic, Neues Jahrbuch für Mineralogie, Abhandlungen 175, 105-124.

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