Mineral - Fairfieldite
Fairfieldite
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
Ca₂Mn²⁺(PO₄)₂ · 2H₂O
Unit Cell
a=5.79 b=6.57 c=5.51 α=102° β=108° γ=90° Z=1
Physical Properties
Hardness
3.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {001}, distinct after {010} and {1 1 0}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
whitecolorless
Birefringence
0.020
Luster
Vitreous,
Pearly,
Waxy
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
triclinic
Point Group
triclinic-pinacoidal - 1
Space Group
P 1 (2)
Habit
leafy, coarse, spherical, massive, tabular
Formation
As a secondary mineral through the alteration of primary phosphates in granitic pegmatites, resulting from the interaction with Ca-rich hydrothermal fluids during late magmatic stages
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Fairfieldite
Composition
Elements
Mass
P₂O₅
38.39
FeO
5.62
MnO
15.55
CaO
28.85
Na₂O
0.73
K₂O
0.13
H₂O
9.98
Connecticut (Palache et al. 1952)
Groups and Members
Kröhnkite-Supergroup
Fairfieldite-Group