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Kaňkite

FieldValue
nameKankite
imageKaňkite.jpg
captionKaňkite found in the Czech Republic
categoryArsenate mineral
formulaFe3+AsO4·3.5(H2O)
IMAsymbolKňk
molweight257.82 g/mol
strunz8.CE.60
systemMonoclinic
Unknown space group
unit cella = 18.803(15), b = 17.490(18)
c = 7.633(5) [Å]; β = 92.72°; z = 16
colorYellowish–green
habitTabular spearlike crystals in spherulites and botryoidal encrustations
fractureUneven
mohs2–3
lusterDull to vitreous
streakGrayish yellow
diaphaneityTranslucent
gravity2.60 – 2.70
opticalpropBiaxial
refractivenα = 1.664 nγ = 1.680
references

Unknown space group c = 7.633(5) [Å]; β = 92.72°; z = 16 | length fast/slow =

Kankite is a mineral with the chemical formula Fe3+AsO4·3.5(H2O). Kankite is named for the locality that yielded first specimens Kaňk, Czech Republic. Kankite formation is associated with old (1200- to 1400-year-old) mine dumps. It is yellowish-green on fresh exposure, with a paler greenish yellow on exposure to air.

Properties

Kankite is a monoclinic mineral, meaning it is a mineral system having 3 unequal axes of which one is at right angles with the other two. It has an uneven fracture and has a hardness of 2–3 (gypsum–calcite). It is translucent yellowish green in color with a grayish-yellow streak. Its luster is dull to vitreous. Kankite contains the elements arsenic, iron, hydrogen and oxygen. It was approved by the IMA in 1976. Its habit is botryoidal, "grape-like" rounded forms (e.g. malachite). It forms encrustations, crust-like aggregates on matrix. The specific gravity of Kankite is 2.70.

Occurrences

Kankite was first described in 1976 for an occurrence in the Kaňk, Kutná Hora, Bohemia, Czech Republic. It is a rare secondary mineral in highly weathered mine dumps containing arsenopyrite (in the Czech Republic). It occurs in association with scorodite, pitticite, parascorodite, zykaite, arsenopyrite, vajdakite, native arsenic, pyrite, proustite, gypsum, “limonite” and quartz.

It has also been reported from Munzig near Meissen; from Brand-Erbisdorf, Saxony; from Menzenschwand, Black Forest in Germany. It occurs at King's Wood mine, Buckfastleigh, Devon, and from the South Terras mine, St. Stephen-in-Brannel, Cornwall in England. It has also been reported from the Suzukura mine north-northeast of Enzan, Yamanashi Prefecture, Japan.

References

Category_Minerals described in 1976

References

  1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
  2. [http://handbookofmineralogy.org/pdfs/kankite.pdf Handbook of Mineralogy]
  3. [http://webmineral.com/data/Kankite.shtml Webmineral data]
  4. [http://mindat.org/min-2153.html Mindat.org]
  5. [http://eprints.qut.edu.au/], Frost, Ray L. and Cejka, Jin and Keeffe, Eloise C. and Sejkora, Jiri (2009)''Raman Spectroscopic study of the mixed anion sulphate-arsenate mineral pamnauite''Journal of Raman Spectroscopy, 40(11) pp. 1547–1550.
Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

iron(iii)-minerals arsenate-minerals hydrate-minerals monoclinic-minerals
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