Pyrite

Pyrite is most commonly known as “Fool’s Gold”. Pyrite is a secondary source for sulfur. During WWII, deposits of iron pyrite were mined for its sulfur and iron. Pyrite could be used as an ore for iron, but hematite and magnetite are more economical to mine and therefore they are primary ores.

The brightly colored reds, blues and greens are an optical anomaly. They are not a characteristic of pyrite under normal viewing conditions.

Color: Brass-yellow, gray-yellow

Color of streak: Green-Black

Moh’s hardness: 6 to 6 1/2

Density: 5 to 5.2 grams/cubic centimeter

Cleavage: Indistinct

Fracture: Conchoidal, uneven, brittle

Crystal system: Cubic, pentagonal, dodecahedra, octahedral

Chemical composition: FeS2, iron sulfide

Transparency: Opaque

Refractive index: Cannot be determined

Double refraction: None

Dispersion: None

Pleochroism: Absent

Absorption spectrum: Not diagnostic

Fluorescence: None