afghanite
afghanite crystal from Afghanistan
afghanite crystal from Afghanistan
inclusions of lazurite small crystals
Detailed sheet
afghanite
Named after the country where it has been discovered, Afghanistan. Often confused with lapis lazuli (lazurite), lazulite or sodalite.
CHEMICAL CHARACTERISTICS
(Na,Ca,K)8[(Si,Al)12O24)] (H2O) (SO4,Cl,CO3)3
complex alumino silicate
PHYSICAL CHARACTERISTICS
Main color
blue
only in blue shades
Color of streak
white
Luster
vitreous
Hardness
5.5 to 6.0
Density
2.55 to 2.65
Cleavage
perfect
Fracture
uneven
OPTICAL PROPERTIES
Transparency
transparent
Refractive index
1.530 - 0.000
Double refraction
0.006
very weak, uniaxial (+)
visible double refraction
No
Pleochroism
absent
Number of colors
1
Fluorescence
none
CRYSTALS PROPERTIES
short prisms often biterminated
crystals system
hexagonal
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
Found in Afghanistan in the Koksha valley in Badakhshan, but also in Canada in the Baffin island, in Germany (Palatinat), in Italy, in Pamir massif in Tadjikistan.
use in jewelry
gemstone for collectors.
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