Sodalite
Chemical Formula	Na?Al?Si?O??Cl
Species	Silicates
Crystal System	Isometric
Mohs Scale	5-6
Specific Gravity	2.27-2.33
Color	Rich royal blue, green, yellow, Purple, white veining common
Streak	White
Luster	Vitreous, Greasy
Refractive Index	n = 1.483 - 1.487
Diaphaneity	Transparent, Translucent
Cleavage	Poor/IndistinctPoor on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Massive; rarely as dodecahedra
Geological Setting：Sodalites occur: - in alkaline intrusives (Princess Mine, Bancroft, Ontario, Canada); - in alkaline pegmatites (Mont St Hilaire, Quebec, Canada); - in carbonatites (Magnet Cove, Arkansas, USA); - in marble skarns or metasomatized calcareous rocks (Ladjuar Medan, Sar-e-Sang, Afghanistan); - in phonolites and volcanic ejecta (Mount Vesuvius, Italy).