Mineral - Pyrite
Pyrite
Chemical Properties
Mineral Class
Sulfides and sulfosalts
Toxicity
none
Formula
FeS₂
Unit Cell
a=5.42 Z=4
Physical Properties
Hardness
6 - 6.5
Streak
blackgreengreen black
Density
Heavy (3,5-6)
Cleavage
Indistinct after {100}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
yellowgold
Birefringence
Luster
Metallic
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
isometric
Point Group
diploidal - 2/m 3
Space Group
Pa 3 (205)
Habit
Deltoidal icositetrahedron, dodecahedron, wedge-shaped, spherical, Octahedron, radial, skeletal, Cube
Formation
(1) Magmatic, as an early precipitation resulting from the separation of sulfides from mafic to ultramafic melts.
(2) Hydrothermal, by precipitation from metal-bearing fluid phases over a wide temperature range in association with magmatic or metamorphic processes.
(3) Sedimentary-syngenetic, under anoxic conditions through bacterial reduction of sulfate and reaction with dissolved iron in pore waters.
(4) Metamorphic, through the recrystallization of pre-existing sulfides under increasing pressure-temperature conditions (up to the granulite facies).
Paragenesis
Twinning
Penetration twins after {110} - Iron Cross Law
Rarity
Very common
Synonyms
Pyrite
Composition
Elements
Mass
Fe
46.49
S
53.49
Italy (Palache et al. 1952)
Groups and Members
Pyrite-Group