Afghanite

Afghanite, (Na,Ca,K)8(Si,Al)12O24(SO4,Cl,CO3)3·H2O, is a hydrous sodium, calcium, potassium, sulfate, chloride, carbonate alumno-silicate mineral. Afghanite is a feldspathoid of the cancrinite group and typically occurs with sodalite group minerals. It forms blue to colorless, typically massive crystals in the hexagonal crystal system. It has a Mohs hardness of 5.5 to 6 and a specific gravity of 2.55 to 2.65. It has refractive index values of nω=1.523 and nε=1.529. It has one direction of perfect cleavage and exhibits conchoidal fracture. It fluoresces a bright orange.
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General Information:
 Chemical Formula:
(Na,Ca,K)8(Si,Al)12O24(SO4,Cl,CO3)3·(H2O)
 Environment:
Generally associated with sodalite-group minerals.
 IMA Status:
Approved IMA 1968
 Locality:
TL: Sar-e-Sang luzurite deposit in Afghanistan.
 Name Origin:
From its locality.
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
blue or colorless.
 Density:
2.55 - 2.65, Average = 2.59
 Diaphaniety:
Transparent
 Habits:
Massive - Uniformly indistinguishable crystals forming large masses., ,
 Hardness:
5-6 - Between Apatite and Orthoclase
 Luster:
Vitreous (Glassy)
 Streak:
white
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