Pyrite

The name pyrite comes from the Greek word pyr, meaning fire, since sparks are caused if pyrite is struck with a hammer.

With its brassy yellow color, pyrite is often mistaken for gold (hence its other name is fool's gold). It occurs as cubes, or as "pyritohedra", which have twelve faces, each with five edges. Pyrite has been used in jewelry for thousands of years, and examples from the ancient civilization of the Greeks, Romans, and Incas have been found. Today it is used mainly in costume jewelry, but is brittle and requires careful cutting.

Pyrite is found worldwide in igneous, metamorphic, and sedimentary rocks. Fine specimens come from Spain, Mexico, Peru, Italy, and France.

Pyrite Pictures

Pyrite cubeIron pyrite mineralPyrite showpiece

Pyrite Properties

Chemical Composition: 
Iron Sulphide - FeO2
Classification / Type: 
Dimorph of Marcasite
Colors / Varieties: 
Brassy Yellow
Crystal System / Forms: 
Cubic System / Pyritohedron: Pentagon-dodecahedron, cubes, combination of forms
Hardness: 
6 - 6.5
Specific Gravity: 
4.95 - 5.10
Cleavage / Fracture: 
Indistinct / Conchoidal to Uneven fracture
Optic Character: 
Opaque
Lustre: 
Metallic
Magnification: 
Three sets of parallel oscillatory striations on adjacent faces.
U.V. Fluorescence: 
Inert
Cause of Color: 
Iron
Specific Tests: 
Greenish black streak, yellow color with metallic lustre.
Simulants (with separation tests): 
Marcasite (S.G., orthorhombic crystal system)
Geological Occurrence: 
Abundant occurrence in all types of rocks - igneous, sedimentary and metamorphic rocks.
Sources: 
Italy, England, Norway, Sweden, Switzerland, U.S.A.
Cuts & Uses: 
Cabochons, cameos, beads, facetted cuts.