ගිනිබොකු තෝර

විකිපීඩියා, නිදහස් විශ්වකෝෂය වෙතින්
වෙත පනින්න: සංචලනය, සොයන්න
ගිනිබොකු තෝර
Andalusite, Tyrol Austria.
General
Category Nesosilicates
රසායනික සූත්‍රය Al2SiO5
Strunz classification 09.AF.10
Crystal symmetry 2/m 2/m 2/m - Dipyramidal
Unit cell a = 7.7980 Å b = 7.9031 Å c = 5.5566 Å; Z = 4
Identification
පාට / පැහැය Pink, violet, yellow, green, white, gray; in thin section, colorless to pink or green
Crystal habit As euhedral crystals or columnar aggregates having nearly square cross sections; fibrous compact to massive
Crystal system orthorhombic
Twinning On {101}, rare
Cleavage Good on {110}, poor on {100}
Fracture uneven to subconchoidal
Mohs scale hardness 6.5 - 7.5
Luster Vitreous
Streak White
Diaphaneity Transparent to nearly opaque with inclusions
Specific gravity 3.17 (+/- .04)
Optical properties double refractive, biaxial negative; chiastolite has anomalous aggregate reaction.[1]
Refractive index nα = 1.629 - 1.640 nβ = 1.633 - 1.644 nγ = 1.638 - 1.650
Birefringence δ = 0.009 - 0.010
Pleochroism Weak
2V angle 71 - 86°
Dispersion r < v strong
Ultraviolet fluorescence non-fluorescent
References [1][2][3][4]
  1. 1.0 1.1 Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
  2. http://rruff.geo.arizona.edu/doclib/hom/andalusite.pdf Handbook of Mineralogy
  3. http://www.mindat.org/show.php?id=217&ld=1&pho= Mindat.org
  4. http://webmineral.com/data/Andalusite.shtml Webmineral data
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