Rock Identifier
Sodalite (Sodalite (Na8Al6Si6O24Cl2)) — mineral
mineral

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Hardness: 5.5-6 on Mohs scale; Color: typically rich royal blue with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric; Cleavage: Poor; Specific Gravity: 2.27-2.33.

Hardness
5
Color
typically rich royal blue with white calcite veining
Luster
Vitreous to greasy
Identified More mineral

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Physical properties

Hardness: 5.5-6 on Mohs scale; Color: typically rich royal blue with white calcite veining; Luster: Vitreous to greasy; Crystal Structure: Isometric; 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 of limestone. It is a tectosilicate mineral that crystallizes from alkali-rich magmas.

Uses & applications

Used primarily as an ornamental gemstone for jewelry (beads, cabochons), carvings, sculptures, and architectural surface cladding or countertops.

Geological facts

Sodalite was first discovered in Greenland in 1811 but became stones of importance in 1891 when large deposits were found in Ontario, Canada. It is often confused with Lapis Lazuli, but Sodalite lacks the golden pyrite inclusions common in Lapis.

Field identification & locations

Identify in the field by its distinct royal blue color and characteristic white calcite streaks. Unlike many other blue minerals, it will often fluoresce a bright orange-red under long-wave UV light. Common locations include Canada (Bancroft), Brazil, Namibia, and Russia.