Lazulite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameLazulite
Chemical Formula(Mg,Fe2+)Al2(PO4)2(OH)2
Mohs Hardness5.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
Cleavagedistinct on {110}
Fractureuneven
Specific Gravity3.1
Colorsblue, greenish-blue, dark blue
Transparencytransparent
Type LocalityGraves Mountain, Lincoln County, Georgia, USA
Mineral Groupphosphates
Usescollector, minor gemstone
Associated Mineralsquartz, rutile, kyanite, pyrophyllite
Rarityuncommon
Description
This specimen is a dark blue to greenish-blue lazulite crystal, possibly twinned, exhibiting a granular texture with scattered white inclusions. It has a somewhat blocky, angular form.
Geological Context
Lazulite typically forms in high-grade metamorphic rocks, such as quartzites, and sometimes in pegmatites. It is an indicator mineral for certain metamorphic conditions.
