cubic Tectosilicates
Lazurite (Crystal form (rare))
Formula Na3Ca(Al3Si3O12)S
Crystal Structure
#! Species: Lazurite
#! System: Cubic (m3m)
#! Habit: Dodecahedral crystals (extremely rare)
cubic[m3m]:{110}@1.0 + {100}@0.3
cubic
m3m
{110} {100}
Quick Facts
Hardness
5.0
Specific Gravity
2.38
Refractive Index
1.5
Optical Character
Isotropic
Physical Properties
- Crystal System
- cubic
- Hardness (Mohs)
- 5.0
- Specific Gravity
- 2.38
- Cleavage
- Imperfect {110}
- Fracture
- Uneven
- Lustre
- Vitreous to greasy
Optical Properties
- Refractive Index
- 1.5
- Optical Character
- Isotropic
- Pleochroism
- None (isotropic)
Characteristics
Colours
Deep blueAzure blueViolet-blueGreenish-blue
Localities
Afghanistan (Badakhshan - type locality, 6000+ years of mining)Chile (Andes)Russia (Lake Baikal)MyanmarUSA (California, Colorado)
Crystal Forms
dodecahedroncube
Notes
Well-crystallized specimens extremely rare; usually occurs massive in lapis lazuli rock
Related Minerals
Other minerals in the cubic system
