Lazulite - (Mg,Fe2+)Al2(PO4)2(OH)2

Named in 1795 by Marten H. Klaproth from the term "Lazaward", which means heaven in Arabic, in allusion to its colour. Austria is the type locality of Lazulite, with the noteworthy localities of Fischbach, in Styria. In Italy, Lazulite comes from the Vizze pass, Bolzano Province; and from Monte Folgorito, Pietrasanta, Lucca Province. Lazulite is in a solid solution series with the mineral scorzalite. The lazulite-scorzalite series ranges from the magnesium rich lazulite to the iron rich scorzalite. The rarer scorzalite does not differ appreciably, except that it tends to be darker, less transparent and denser than lazulite.

It forms by high grade metamorphism of high silica quartz rich rocks and in pegmatites. It occurs in association with quartz, andalusite, rutile, kyanite, corundum, muscovite, pyrophyllite and dumortierite, in metamorphic terrains. It may be confused with lazurite (a blue feldspathoid and a member of the sodalite group) or azurite (deep blue copper carbonate).

Optical Properties:

• Habits: Dipyramidal crystal. Also granular and massive.
• Color: Azure-blue, sky-blue, bluish white, yellow-green, blue-green, rarely green.
• Pleochroism: Strong, from colorless to blue and darker blue.
• Birefringence: High, II-III order.

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Deep-blue lazulite crystals, Horsjoberg, Varmland, Sweden. Immagine tratta da RRUFF.



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Deep-blue lazulite crystals, Champion mine, White Mountains, Mono County, California, USA. Immagine tratta da RRUFF.



Bibliography



• Bucher, K., & Grapes, R. (2011). Petrogenesis of metamorphic rocks. Springer Science & Business Media.
• Fossen, H. (2016). Structural geology. Cambridge University Press.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Passchier, Cees W., Trouw, Rudolph A. J: Microtectonics (2005).
• Philpotts, A., & Ague, J. (2009). Principles of igneous and metamorphic petrology. Cambridge University Press.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.
• Vernon, R. H. (2018). A practical guide to rock microstructure. Cambridge university press.


Photo
lazulite2016(3).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(4).jpg

Lazulite crystals (high birefringence) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(5).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(6).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(7).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(8).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(6).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(7).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(8).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(10).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(11).jpg

Lazulite crystals (high birefringence) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(12).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(13).jpg

Lazulite crystals (high birefringence) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(16).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(17).jpg

Lazulite crystals (high birefringence) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(18).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(19).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(20).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)
lazulite2016(14).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(15).jpg

Lazulite crystals (high birefringence) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 2x (Field of view = 7mm)		 lazulite2016(22).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)
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Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. XPL image, 10x (Field of view = 2mm)		 lazulite2016(24).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)		 lazulite2016(25).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. XPL image, 10x (Field of view = 2mm)
lazulite2016(26).jpg

Lazulite (azure-blue) and kyanite crystals in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)		 lazulite2016(27).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)		 lazulite2016(28).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)
lazulite2016(29).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)		 lazulite2016(30).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)		 lazulite2016(31).jpg

Lazulite crystals (azure-blue) in a impure quartzite from the Vizze pass, Bolzano Province, Italy. PPL image, 10x (Field of view = 2mm)