igneous

Sodalite

Sodalite: Na8(Al6Si6O24)Cl2

Hardness: 5.5-6 (Mohs). Color: Royal blue to gray-blue, often with white calcite veining. Luster: Vitreous to greasy. Crystal structure: Isometric. Cleavage: Poor. Specific Gravity: 2.27-2.33.

Hardness: 5
Color: Royal blue to gray-blue, often with white calcite veining
Luster: Vitreous to greasy

Identified May 10, 2026More igneous →

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Physical properties

Hardness: 5.5-6 (Mohs). Color: Royal blue to gray-blue, often 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 occur in contact metamorphosed limestones. Most deposits are Precambrian to Paleozoic in age.

Uses & applications

Commonly used as a gemstone for jewelry (cabochons, beads, earrings), ornamental carvings, and as a decorative architectural stone.

Geological facts

Sodalite was first discovered in Greenland in 1811 but became popular in 1891 when large deposits were found in Ontario, Canada, earning it the nickname Princess Blue after Princess Margaret of England.

Field identification & locations

Identify by its intense blue color and lack of pyrite inclusions (which distinguishes it from Lapis Lazuli). It may fluoresce a bright orange or yellow under UV light. Found in Canada, Brazil, Namibia, and Russia.

Other igneous specimens

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous