Rock Identifier
Sodalite (Chloric sodium aluminum silicate (Na8(Al6Si6O24)Cl2)) — mineral
mineral

Sodalite

Chloric sodium aluminum silicate (Na8(Al6Si6O24)Cl2)

Hardness: 5.5-6.0 Mohs; Color: Royal blue with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric/Cubic; Cleavage: Poor; Specific Gravity: 2.27-2.33.

Hardness
5
Color
Royal blue with white calcite veining
Luster
Vitreous to greasy
Identified More mineral

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Physical properties

Hardness: 5.5-6.0 Mohs; Color: Royal blue with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric/Cubic; Cleavage: Poor; Specific Gravity: 2.27-2.33.

Formation & geological history

Formed in silica-poor igneous rocks such as nepheline syenites and phonolites. It can also form during metasomatism in contact-metamorphosed limestones.

Uses & applications

Primarily used as a gemstone, for ornamental carvings, architectural finishes (countertops/tiles), and as a pigment in some historical applications.

Geological facts

Sodalite is a member of the sodalite group including hauynite and lazurite. It was discovered in Greenland in 1811 but became popular in 1891 when large deposits were found in Ontario, Canada, during a royal visit.

Field identification & locations

Identify by its deep blue color and characteristic white calcite streaks. It lacks the gold pyrite inclusions typically found in Lapis Lazuli. It will often fluoresce orange under short-wave UV light.