Mineral - Rhodonite
Rhodonite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
CaMn₃Mn[Si₅O₁₅]
Unit Cell
a=9.76 b=10.50 c=12.21 α=109° β=103° γ=83° Z=20
Physical Properties
Hardness
5.5 - 6.5
Streak
white
Density
Heavy (3,5-6)
Cleavage
Perfect after {110} and {1 1 0}, distinct after {001}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
redpink
Birefringence
0.013
Luster
Greasy,
Pearly
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
triclinic
Point Group
triclinic-pinacoidal - 1
Space Group
P 1 (2)
Habit
leafy, blocky, wedge-shaped, massive, prismatic, tabular
Formation
(1) Metamorphic in manganese-rich, siliceous sediments through regional or contact metamorphism (up to the amphibolite facies).
(2) Metasomatic in hydrothermal ore deposits through the reaction of manganese-bearing fluids with silicate rocks
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Rhodonite
Composition
Elements
Mass
SiO₂
45.46
Al₂O₃
0.27
FeO
0.96
MnO
50.54
ZnO
0.01
MgO
0.55
CaO
2.25
India (Dana 1895)
Groups and Members
Rhodonite-Group