Mineral - Siderite
Siderite
Chemical Properties
Mineral Class
Carbonates
Toxicity
none
Formula
Fe[CO₃]
Unit Cell
a=4.69 c=15.39 Z=6
Physical Properties
Hardness
4
Streak
white
Density
Heavy (3,5-6)
Cleavage
Perfect after {10 1 1}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
blackbrownyellow
Birefringence
0.242
Luster
Vitreous,
Pearly
Transparency
translucent,
transparent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
ditrigonal-scalenohedral - 3 m
Space Group
R 3 c (167)
Habit
blocky, Rhombohedron, rosette, tardy
Formation
(1) Hydrothermal, through precipitation from iron-rich solutions in ore veins or through metasomatic replacement of carbonate rocks (siderite metasomatism),
(2) Sedimentary, under reducing (anoxic), low-sulfide conditions in fine-grained sediments or as diagenetic concretions.
Paragenesis
Twinning
Rarity
Common
Synonyms
Siderite
Composition
Elements
Mass
CO₂
38.19
FeO
61.08
MnO
1.12
MgO
0.13
CaO
0.10
England (Palache et al. 1952)
Groups and Members
Calcite-Group