Garronite

General Information:
 Chemical Formula:
Na2Ca5Al12Si20O64·27(H2O)
 Composition:
(Molecular Weight = 2,642.23 gm)
Sodium 1.74 % Na
Calcium 7.58 % Ca
Aluminum 12.25 % Al
Silicon 21.26 % Si
Hydrogen 2.06 % H 
Oxygen 55.10 % O 
 Empirical Formula:
Na2Ca5Al12Si20O64·27(H2O)
 IMA Status:
Approved IMA 1962
 Name Origin:
Named after its locality in Garron Plateau, Northern Ireland.
Physical Properties:
 Cleavage:
[???] Good, [???] Good
 Color:
colorless or white.
 Density:
2.1 - 2.2, Average = 2.15
 Diaphaniety:
Transparent to Translucent
 Habits:
Acicular - Occurs as needle-like crystals., Massive - Fibrous - Distinctly fibrous fine-grained forms., Radial - Crystals radiate from a center without producing stellar forms (e.g. s tibnite)
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Vitreous (Glassy)
 Streak:
white
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