Lazulite

n. azure-blue mineral

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.
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n. (Port.=lazulite) lapis lazuli, type of blue gemstone

(n.)
A mineral of a light indigo-blue color, occurring in small masses, or in monoclinic crystals; blue spar. It is a hydrous phosphate of alumina and magnesia.
  

General Information:
 Chemical Formula:
MgAl2(PO4)2(OH)2
 Composition:
(Molecular Weight = 302.23 gm)
Magnesium 8.04 % Mg
Aluminum 17.86 % Al
Phosphorus 20.50 % P 
Hydrogen 0.67 % H 
Oxygen 52.94 % O 
 Empirical Formula:
MgAl2(PO4)2(OH)2
 Name Origin:
From the Arabic azul - "sky" and the Greek lithos - "stone."
Physical Properties:
 Cleavage:
[001] Indistinct, [???] Indistinct
 Color:
blue, blue green, light blue, or black blue.
 Density:
3 - 3.1, Average = 3.05
 Diaphaniety:
Subtranslucent to opaque
 Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Pyramidal - Crystals are shaped like pyramids.,
 Hardness:
5-6 - Between Apatite and Orthoclase
 Luminescence:
None.
 Luster:
Vitreous (Glassy)
 Streak:
white
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