The mineral sodalite is named for its sodium content. As a gemstone, sodalite is usually a deep blue, often with a violet tint, and frequently contains white veins of calcite.
Sodalite was first discovered in Greenland in 1806. It did not become important as an ornamental stone until 1891 when large deposits of fine material were discovered in the province of Ontario in Canada.
Well known in the gemstone world for its rich royal blue color, sodalite may also be grey, yellow, green, or pink and is often mottled with white veins or patches. The more uniformly blue material is used in jewelry, where it is fashioned into cabochons and beads. Lesser material is more often used as facing or inlay in decorative objects.
Gemologically, sodalite is a chloric sodium aluminum silicate with a hardness of 5.5 to 6 on the Mohs scale. It has a specific gravity of 2.14-2.40, making it one of the least dense of all gemstone materials, just slightly denser than opal. Sodalite is typically opaque with a vitreous luster and a refractive index of 1.48.
Sodalite can sometimes be confused with lapis lazuli. Unlike sodalite, lapis is a rock rather than a mineral. Lapis is typically composed of 3 minerals: lazurite, calcite and pyrite. Sometime lapis contains sodalite as well. While the colors of sodalite and lapis have some similarities, sodalite tends more towards a violet blue and never has inclusions of pyrite.
Sodalite is found in Brazil, Greenland, India, Canada, the USA (Montana), Namibia and Russia.
- First Published: March-04-2009
- Last Updated: March-02-2011
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