HISTORY, NAME, LOCALITIES: Pyrite has been known since antiquity. Its name stems from the Greek pyr, or “fire,” alluding to its ability to spark when struck with metal. Collecting localities are found in Peru, Italy, Brazil, Spain, Germany, Bolivia, China, and the United States (Colorado, Missouri, Kansas, Illinois, Kentucky, Idaho).
MINERALOGY, PROPERTIES, OCCURRENCE: Pyrite [iron disulfide, FeS2], pronounced PIE-rite, is the most abundant sulfide mineral. It crystallizes in the cubic system as individual or clustered cubes, pyritohedra, or octahedra, and also occurs in massive, concretionary, and nodular forms. It has a Mohs hardness of 6.0-6.5, no cleavage, and a specific gravity of 4.9-5.2. Crystals are striated, opaque, and have a pale, brass-yellow color that tarnishes to brown. Pyrite occurs in all mineralogical environments; the best crystals develop in hydrothermal veins in association with quartz, sphalerite, and galena.
METAPHYSICAL PROPERTIES, LORE, USES: Metaphysical practitioners believe that pyrite supplements physical energy with the energy of the sun, increases stamina, stimulates the intellect, and protects against negativity and risk. It is a former ore of both iron and sulfur. It now has only limited use as a coloring agent in the manufacture of amber glass. Once a popular Victorian-era gemstone, pyrite still has minor uses in jewelry.
COLLECTORS’ INFORMATION. Pyrite is widely collected for its affordability, variety of crystal habits, bright metallic luster, crystal size, perfection of cubic crystal form, and frequent occurrence in beautiful composite specimens with such minerals as quartz, galena, and sphalerite.