sodalite

Sodalite is a rich royal blue mineral widely enjoyed as an ornamental stone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group and together with hauyne, nosean and lazurite is a common constituent of lapis lazuli.
See more at Wikipedia.org...

Noun
1. a vitreous mineral consisting of sodium aluminum silicate and sodium chloride in crystalline form; occurs in igneous rocks
(hypernym) mineral
(substance-holonym) igneous rock

(n.)
A mineral of a white to blue or gray color, occuring commonly in dodecahedrons, also massive. It is a silicate of alumina and soda with some chlorine.
  

General Information:
 Chemical Formula:
Na8Al6Si6O24Cl2
 Composition:
(Molecular Weight = 933.76 gm)
Sodium 19.70 % Na
Aluminum 17.34 % Al
Silicon 18.05 % Si
Chlorine 3.80 % Cl
Oxygen 41.12 % O 
 Empirical Formula:
Na8Al6Si6O24Cl
 Locality:
Miask in the Ilmen Mountains, Russia.
 Name Origin:
Named from its chemical composition.
Physical Properties:
 Cleavage:
[110] Poor
 Color:
azure blue, white, pink, gray, or green.
 Density:
2.29
 Diaphaniety:
Transparent to translucent
 Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Disseminated - Occurs in small, distinct particles dispersed in matrix.,
 Hardness:
6 - Orthoclase
 Luminescence:
None.
 Luster:
Vitreous - Greasy
 Streak:
white
More details...

SODALITE