Mineral - Armstrongite
Armstrongite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
CaZr[Si₆O₁₅] · 3H₂O
Unit Cell
a=14.02 b=14.13 c=7.84 β=109° Z=4
Physical Properties
Hardness
4.5
Streak
whitebrown white
Density
Normal (2-3,5)
Cleavage
Perfect after {001}, good after {100}
Fracture
Tenacity
Brittle
Optical Properties
Color
brown
Birefringence
0.010
Luster
Vitreous
Transparency
translucent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/m (12)
Habit
leafy, coarse, lamellar, lath-shaped, massive, prismatic, tabular
Formation
Magmatic, in pegmatites
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Armstrongite
Composition
Elements
Mass
SiO₂
60.12
TiO₂
0.12
ZrO₂
19.80
Al₂O₃
0.60
(REE)₂O₃
0.55
Fe₂O₃
1.31
MgO
0.19
MnO
9.15
CaO
0.18
Na₂O
0.14
K₂O
7.90
H₂O
0.20
Mongolia (Vladykin et al. 1973)
Name and first find : Named after the American astronaut and first man on the moon, Neil Alden Armstrong (1930-2012). First found at the type locality in 1972.
Chemistry :
Synonyms :
Varieties :
Abbreviation : Asg
literature
Vladykin, NV, VI Kovalenko, AA Kashaev, AN Sapozhnikov, and VA Pisarskaya (1973) A new mineral of calcium and zirconium, armstrongite. Doklady Acad. Nauk SSSR , 209, 1185-1188