Lazulite

Lazulite ((Mg,Fe²⁺)Al₂(OH,PO₄)₂) is a blue, phosphate-based mineral containing magnesium, iron, and aluminium phosphate. Lazulite forms one endmember of a solid solution series with the darker iron rich scorzalite.

It forms by high grade metamorphism of high silica quartz rich rocks and in pegmatites. It is considered a semi-precious gemstone. It is often confused with lazurite, lapis lazuli or azurite.

Lazulite crystallizes in the monoclinic system with prismatic crystals, although it is usually massive in form. It has a Mohs hardness of 5.5 to 6 and a specific gravity of 3.0 to 3.1. It is infusible and insoluble.

It is found in Salzburg, Austria; Zermatt, Switzerland; Minas Gerias, Brazil; Lincoln County, Georgia; Inyo County, California; the Yukon in Canada, and elsewhere.

It was first described in 1795 for deposits in Austria. Its name comes from the Arabic for heaven.

References

• Hurlbut, Cornelius S.; Klein, Cornelius, 1985, Manual of Mineralogy, 20th ed., Wiley, ISBN 0-471-80580-7
• The Mineral Database
• Lazulite - Mineral Galleries
• Minerals-n-More
• Webmineral data
• Lazulite localities, from Mindat