Rock Identifier
Sodalite (Sodalite (Na8(Al6Si6O24)Cl2)) — mineral
mineral

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Hardness: 5.5-6.0 Mohs; Color: Royal blue to gray, often with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric; Cleavage: Poor; Specific Gravity: 2.2-2.3.

Hardness
5
Color
Royal blue to gray, often 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 to gray, often with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric; Cleavage: Poor; Specific Gravity: 2.2-2.3.

Formation & geological history

Formed in silica-poor igneous rocks, particularly nepheline syenites and pegmatites. It crystallizes from sodium-rich hydrothermal solutions or magmatic fluids.

Uses & applications

Used primarily as an ornamental stone, in jewelry (cabochons and beads), and as a collector's mineral specimen. Historically used for making flooring, countertops, and small sculptures.

Geological facts

Sodalite is often confused with Lapis Lazuli, but it lacks the golden pyrite flecks of Lapis and has a lower specific gravity. It is the most common member of the sodalite mineral group, which also includes tugtupite and hauyne.

Field identification & locations

Identify in the field by its characteristic rich blue color and association with white calcite streaks. Unlike Lapis, it almost never contains pyrite. It may fluoresce orange under ultraviolet light (longwave). Commonly found in Canada (Ontario), Brazil, Namibia, and Russia.