Sodalite

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MFA# 2012.50

Description

Sodalite

A blue, glassy mineral of sodium aluminum silicate that has been used as a Gemstone and for ornamentation. Sodalite was discovered in Greenland in 1806. It is produced in soda rich magmas and other deposits have been found near Vesuvius, in Norway, Romania, Portugal, Russia, Bolivia, Brazil, Canada (Ontario, Quebec, British Columbia) and the U.S. (Maine). Sodalite resembles Lapis lazuli, but is harder and does not contain the gold colored iron Pyrite flecks. Hackmanite, a variety of sodalite, fades to white when exposed to light but will regain its dark blue color when left in the dark.

Synonyms and Related Terms

scapolite; Princess blue; hackmanite; sodalita (Esp.); sodalite (Fr., Port.); Sodalit (Deut.)

FTIR (PMA)

Raman (Rasmin)

Physical and Chemical Properties

• Cubic system found as masses or rarely as dodecahedrons.
• Fracture = conchoidal to uneven
• Cleavage = poor
• Luster = vitreous to greasy
• Streak = white
• Fluorescence = patchy orange or red in LW and SW; may have yellowish phosphorescence
• Birefringence = none
• Flame = yellow (sodium color)

Composition	Na4Al3(SiO4)3Cl
Mohs Hardness	5.5 - 6.0
Density	2.14-2.50 g/ml
Refractive Index	1.483-1.487

Additional Images

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  Sodalite

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  Sodalite

Resources and Citations

• Mineralogy Database: Sodalite
• Gem Identification Lab Manual, Gemological Institute of America, 2016.
• Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
• Frank A. Lent, Trade names and Descriptions of Marbles, Limestones, Sandstones, Granites and Other Building Stones Quarried in the United States Canada and other Countries., Stone Publishing Co, New York, 1925
• Encyclopedia Britannica, http://www.britannica.com Comment: "sodalite" [Accessed December 4, 2001].
• C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
• Wikipedia: Sodalite (Accessed Sept. 17, 2005 and Dec 2022)
• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976