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.

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.