cubic Tectosilicates
Sodalite (Crystal form (rare))
Formula Na8(Al6Si6O24)Cl2
Crystal Structure
#! Species: Sodalite
#! System: Cubic (m3m)
#! Habit: Dodecahedral crystals (rare)
cubic[m3m]:{110}@1.0 + {100}@0.5
cubic
m3m
{110} {100}
Quick Facts
Hardness
5.5
Specific Gravity
2.27
Refractive Index
1.483
Optical Character
Isotropic
Physical Properties
- Crystal System
- cubic
- Hardness (Mohs)
- 5.5
- Specific Gravity
- 2.27
- Cleavage
- Poor {110}
- Fracture
- Conchoidal to uneven
- Lustre
- Vitreous to greasy
Optical Properties
- Refractive Index
- 1.483
- Optical Character
- Isotropic
- Dispersion
- 0.018
- Pleochroism
- None (isotropic)
- Fluorescence
- Strong orange (LWUV); tenebrescent (hackmanite variety)
Characteristics
Colours
Royal blueBlueWhiteGrayPinkGreen (rare)
Localities
BrazilCanada (Bancroft, Ontario)NamibiaBoliviaIndiaMyanmar
Crystal Forms
dodecahedroncube
Notes
Well-formed crystals uncommon; sodalite usually occurs as massive aggregates
Related Minerals
Other minerals in the cubic system
