Pyrite (Sulfides)

Pyrite iron sulfide FeS2
pyrite crystal octahedrons			detail of octahedral crystals (note octahedral faces are truncated by cubes)
pyrite "suns": these radiating crystals form in black shales from the reduction of organic matter			pyrite crystal pyritohedrons (photo courtesy of Amethyst Galleries, Inc.)

Diagnostic properties:

Color: pale brass yellow.
Streak: greenish or brownish black.
Hardness: 6 to 6.5.
Specific Gravity: 5.02.
Luster: metallic.
Fracture: conchoidal.
Transparency: opaque.
Occurrence: very common.
Crystal system: isometric.
Uses: A source of sulfur for sulfuric acid. Often mined for its association with gold or copper.
Name: from the Greek word for fire. (It produces brilliant sparks when struck by steel.)

Some images © Copyright 1996 Friends of the Geology Museum and may not be copied for commercial purposes. Permission to copy is granted for personal and educational use only. All such copies must include this copyright notice and explicit references to the URL http://geology.wisc.edu/~museum.

Some images © Copyright 1995-1996 by Amethyst Galleries, Inc. and may not be copied for commercial purposes. Permission to copy is granted for personal and educational use only. All such copies must include this copyright notice and explicit references to the URL http://mineral.galleries.com/.