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cubicuncommonTectosilicates (Feldspathoid group)
Sodalite
Na₄(Al₃Si₃O₁₂)Cl
Sodalite is typically a deep blue mineral, often found in massive form or as dodecahedral crystals, frequently mottled with white veins. In this image, it appears as prominent blue masses within a syenite rock.
Sodalite Physical Properties
Mohs Hardness
5.5Crystal System
cubicLuster
vitreousStreak Color
whiteCleavage
imperfect dodecahedralFracture
conchoidal to unevenSpecific Gravity
2.25Colors
blue, grey, yellow, green, pink, whiteTransparency
transparent to translucentType Locality
Bancroft, Ontario, CanadaMineral Group
Tectosilicates (Feldspathoid group)Uses
jewelry, ornamental stone, collectorAssociated Minerals
nepheline, cancrinite, alkali feldspar, plagioclase, biotiteRarity
uncommonGeological Context
Sodalite forms in silica-undersaturated igneous rocks, particularly alkaline intrusive rocks like nepheline syenites and phonolites, where it crystallizes from magmas lacking sufficient silica to form quartz. It can also occur in contact metamorphic rocks.
