Mineral - Armenite
Armenite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
BaCa₂Al₆Si₉O₃₀ · 2H₂O
Unit Cell
a=13.87 b=18.66 c=10.70 Z=4
Physical Properties
Hardness
7.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {001}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
colorless
Birefringence
0,006
Luster
Vitreous
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pnna (52)
Habit
blocky, prismatic
Formation
Trough the alteration of Ba-rich metamorphic rocks and igneous diorites
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Armenite
Composition
Elements
Mass
SiO₂
46.18
Al₂O₃
27.52
CaO
9.99
SrO
0.04
BaO
12.37
Na₂O
0.16
K₂O
0.13
H₂O
3.52
Canada (Neumann 1939)
Groups and Members
Osumilite-Group
Name and first find : Named after the type locality, the Armen Mine in Norway. First discovered in 1877.
Synonyms :
Varieties :
Abbreviation : Amn
literature
Neumann, H. (1939). Armenite, a new mineral. Preliminary note. Norsk Geol. Tidsskr , 19 , 312-13.