Lazurite - Na6Ca2(Al6Si6O24)(SO4,S,S2,S3,Cl,OH)2

Lazurite, member of the sodalite group, is the blue component of the "gemstone" (or, more usually, decorative rock) Lapis Lazuli, which is a lazurite-calcite-pyrite rock that has been mined as a gem material for some 9.000 years. Lazurite was first described in 1890 for an occurrence in the Sar-e-Sang District, Koksha Valley, Badakhshan Province, Afghanistan. The name Lazurite is derived from the term "Lazaward", which means heaven in Arabic, alluding to its blue color. Lazurite occurs almost exclusively in massive form without any visible crystals. The exception is the historic occurrence of Afghanistan, where this mineral is famous and highly regarded for producing outstanding rich-blue crystals. Lazurite forms a solid solution series with hauyne, essentially sharing the same chemical formula but with a variation of the sulfide over the sulfate. Lazurite has the sulfide dominating, whereas hauyne has the sulfate dominating.

Optical Properties:
Form: Granular, disseminated or massive. Rarely as deodecahedra or cube crystals.
Color: Deep blue.
Relief: Low.
Interference colors: Isotropic, sometime anomalously anisotropic.


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Lazurite crystals. Sar-e-Sang, Afghanistan.



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Lazurite crystals. Sar-e-Sang, Afghanistan.






Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• E. WM. Heinrich (1956): Microscopic Petrografy. Mcgraw-hill book company,inc


Photo
lapislazuli(1).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(2).jpg
Blue lazurite (isotropic, with some anomalously anisotropic blue zones), pyroxene (high interference colors) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. XPL image, 2x (Field of view = 7mm)
lapislazuli(3).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(4).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(5).jpg
Blue lazurite (isotropic, with some anomalously anisotropic blue zones), pyroxene (high interference colors) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. XPL image, 2x (Field of view = 7mm)
lapislazuli(6).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(9).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(10).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(11).jpg
Blue lazurite, pyroxene (beige), pyrite (black) and calcite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 2x (Field of view = 7mm)
lapislazuli(52).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(53).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(58).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(59).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(60).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(66).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(68).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(69).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(74).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(75).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(76).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)
lapislazuli(80).jpg
Blue lazurite crystals in a Lapis Lazuli from Sar-e-Sang, Afghanistan. PPL image, 10x (Field of view = 2mm)