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Lazulite
Current inventory:  1 gem
 

Chemistry:  (Mg,Fe)Al₂(PO₄)₂(OH)₂

Discovered in 1795;   IMA status: Valid (pre-IMA; Grandfathered).
I have found two possibilities for the naming of Lazulite. The first, the name is from the German word lazurstein, meaning blue stone. The second, the name is from the Arabic word azul, meaning sky or heaven, and the Greek word lithos, meaning stone.

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/B.08-20

7 : Phosphates, Arsenates, Vanadates
B : Waterfree phosphates with unfamiliar anions F, Cl, O, OH. cations of very small size: Li, Be
08 : Lazulite group, Trolleite - Richellite

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

As crystals, stubby to acute dipyramidal, to 15 cm, or tabular, with several other forms noted; granular, massive.

Physical Properties

Cleavage:

[110] Poor to Good; [101] Indistinct

Fracture:

Uneven to Splintery

Tenacity:

Brittle

Moh's Hardness:

5.0 - 6.0

Density:

3.122 - 3.240 (g/cm³)

Radioactivity:

Not Radioactive

Optical Properties

Color:

Azure-blue, sky-blue, bluish white, yellow-green, blue-green, rarely green

Transparency:

Transparent to Translucent, Opaque

Luster:

Vitreous

Refractive Index:

1.604 - 1.677  Biaxial ( - )

Birefringence:

0.038 - 0.040

Dispersion:

Weak

Pleochroism:

Strong; X = colorless; Y = blue; Z = darker blue

Occurances

Geological Setting:

Disseminated in metamorphic quartzites, schists and quartz veins; in the border zones of complex granite pegmatites; in alluvium and colluvium.

Type Locality:

Freßnitzgraben, Krieglach, Fischbacher Alpen Mts, Styria, Austria

Year Discovered:

1795

View mineral photos:

Lazulite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Lazulite is a rare gem because most material is opaque and suitable only for cabochons. Transparent rough material suitable for faceted gems is very rare and crystals are quite small and usually heavily included. Lazulite gems from Brazil are small, but a beautiful vivid blue while gems from Pakistan are larger and may be a deep bluish green. Both make for beautiful gems. Lazulite is too soft for jewelry but adds nice color to any gem collection.
 

  
Lazulite gems for sale: