Armstrongite

General Information:
 Chemical Formula:
CaZrSi6O15·3(H2O)
 Composition:
(Molecular Weight = 593.85 gm)
Calcium 6.75 % Ca
Zirconium 15.36 % Zr
Silicon 28.38 % Si
Hydrogen 1.02 % H 
Oxygen 48.50 % O 
 Empirical Formula:
CaZrSi6O15·3(H2O)
 Environment:
Not a lunar mineral. Associated with alkalic rocks.
 IMA Status:
Approved IMA 1973
 Locality:
TL:Khan-Bogdin massif, Mongolia.
 Name Origin:
Named for Neil Alden Armstrong, (1930-), American astronaut, first human being on the moon's surface, Apollo 11 Lunar Mission.
Physical Properties:
 Cleavage:
[001] Perfect, [100] Distinct
 Color:
light brown or reddish brown.
 Density:
2.7 - 2.71, Average = 2.7
 Habits:
Bladed - Aggregates of thin lath-like crystals (e.g. kyanite)., Spherical - Spherical, rounded aggregates., Aggregates - Made of numerous individual crystals or clusters.
 Hardness:
4.5 - Between Fluorite and Apatite
 Luster:
Vitreous (Glassy)
 Streak:
brownish white
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