Gahnospinel

Big Photo

Sri Lanka
0.18 carats
© Giovanni Scapin 2015

Gahnospinel is a zinc-rich variety of Spinel. It has light to dark blue colour.
General Information
A variety or type of:Spinel
Chemical Formula
(Mg,Zn)Al
 
2
O
 
4
Gemdat.org, Management Team (2012)
Photos of natural/un-cut material from mindat.org
Physical Properties of Gahnospinel
Mohs Hardness7.5 to 8
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity3.65 to 4.55
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical Properties of Gahnospinel
Refractive Index1.735 to 1.790
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterIsotropic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Anomalous double refraction
Colour
Colour (General)Blue, bluish-violet, violet
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Causes of ColourBlue, Fe2+ in tetrahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Crystallography of Gahnospinel
Crystal SystemIsometric
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Further Information
Mineral information:Gahnospinel information at mindat.org
Significant Gem Localities
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
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