Siderite - Iron Carbonate
FeCO3

Identifikation

 

Color

Pale yellow to brown

Crystal habit

Tabular crystals

Crystal system

Trigonal - Hexagonal scalenohedral (3 2/m)

Lattice constant

arh   = 6.03 Å     a`103 °, 05`
ahex = 4.72 Å
chex = 15.46 Å

Twinning

Lamellar uncommon on {0112}

Cleavage

Perfect on {0111}

Mohs scale hardness

3.75 - 4.25

Diaphaneity

Translucent to subtranslucent

Specific gravity

3.96

Optical properteis

Uniaxial (-)

Refractive index

n = 1.875
nԑ= 1.633

Birefringence

δ = 0.242