Mineral - Althausite
Althausite
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
(Mg,Ca)₄(PO₄)₂(OH,O)(F,Cl, □)
Unit Cell
a=8.26 b=6.05 c=14.38 Z=8
Physical Properties
Hardness
3.5 - 4
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {001}, distinct after {101}
Fracture
Tenacity
Brittle
Optical Properties
Color
browngrayviolet
Birefringence
0.010
Luster
Vitreous,
Greasy
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pmna (53)
Habit
leafy, coarse, massive, prismatic
Formation
Metamorphism, in serpentinite-magnesite deposits
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Althausite
Composition
Elements
Mass
P₂O₅
43.59
SiO₂
0.11
TiO₂
0.02
Al₂O₃
0.53
Fe₂O₃
1.37
MnO
0.07
MgO
45.38
CaO
4.50
Na₂O
0.22
F
2.86
Cl
0.19
H₂O
1.94
Norway (Raade & Tysseland 1975)
Name and first record : Named after the German mineralogist Egon Althaus (1933-2022). First described in 1974 from its type locality in Norway.
Chemistry :
Synonyms :
Varieties :
Abbreviation : Ahs
literature
Raade, G., & Tysseland, M. (1975). Althausite, a new mineral from Modum, Norway. Lithos , 8 (3), 215-219.