Glaucophane

Glaucophane
Bleu Gemm glaucophane with fuchsite
General
CategoryInosilicates
Sodic amphibole group
Formula
(repeating unit)
☐Na2(Mg3Al2)Si8O22(OH)2
IMA symbolGln[1]
Strunz classification9.DE.25
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Identification
ColorGray, navy blue, lavender-blue
Crystal habitslender long prisms, Massive granular to columnar
CleavageGood on [110] and on [001]
FractureBrittle – conchoidal
Mohs scale hardness6.0–6.5
LusterVitreous – pearly
StreakGrayish blue
DiaphaneityTranslucent
Specific gravity3–3.15
Optical propertiesBiaxial (−)
Refractive indexnα = 1.606 – 1.637 nβ = 1.615 – 1.650 nγ = 1.627 – 1.655
Birefringenceδ = 0.021
PleochroismStrong
DispersionStrong
References[2][3][4][5]

Glaucophane is the name of a mineral and a mineral group belonging to the sodic amphibole supergroup of the double chain inosilicates, with the chemical formula ☐Na2(Mg3Al2)Si8O22(OH)2.

Glaucophane crystallizes in the monoclinic system.

  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. ^ http://rruff.geo.arizona.edu/doclib/hom/glaucophane.pdf Handbook of Mineralogy
  3. ^ http://webmineral.com/data/Glaucophane.shtml Webmineral
  4. ^ "Glaucophane: Glaucophane mineral information and data". www.mindat.org.
  5. ^ Burke, Ernst A.J. "International Mineralogical Association - Commission on New Minerals, Nomenclature and Classification". pubsites.uws.edu.au. Archived from the original on 2015-01-05. Retrieved 2014-05-12.