Danalite

Iron beryllium silicate sulfide mineral
(repeating unit)Fe2+4Be3(SiO4)3SIMA symbolDan[1]Strunz classification9.FB.10Dana classification76.02.04.02Crystal systemIsometricCrystal classHextetrahedral (43m)
H-M symbol: (4 3m)Space groupP43nIdentificationColorYellow, pink, reddish brown, red: colorless to pink in thin sectionCrystal habitOctahedral and dodecahedral crystals, typically massive or as segregationsCleavage{111} and {111}FractureSubconchoidal to unevenTenacityBrittleMohs scale hardness5.5 to 6LusterVitreous or greasyStreakGrey whiteDiaphaneitySemitransparentSpecific gravity3.28 – 3.46Optical propertiesIsotropicRefractive indexn = 1.747 – 1.771References[2][3][4]

Danalite is an iron beryllium silicate sulfide mineral with formula: Fe2+4Be3(SiO4)3S.

It is a rare mineral which occurs in granites, tin bearing pegmatites, contact metamorphic skarns, gneisses and in hydrothermal deposits. It occurs in association with magnetite, garnet, fluorite, albite, cassiterite, pyrite, muscovite, arsenopyrite, quartz, and chlorite.[2]

Danalite was first described in 1866 from a deposit in Essex County, Massachusetts and named for American mineralogist James Dwight Dana (1813–1895).[4]

It has been found in Massachusetts, New Hampshire, Sierra County, New Mexico; Yavapai County, Arizona; Needlepoint Mountain, British Columbia; Walrus Island, James Bay, Quebec; Sweden; Cornwall, England; Imalka and Transbaikal, Russia; Kazakhstan; Somalia; Tasmania; Western Australia and Hiroshima Prefecture, Japan.[2][3]

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. ^ a b c http://rruff.geo.arizona.edu/doclib/hom/danalite.pdf Handbook of Mineralogy
  3. ^ a b http://www.mindat.org/min-1341.html Mindat.org
  4. ^ a b http://webmineral.com/data/Danalite.shtml Webmineral data


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