Pyrite
Pyrite (Iron Disulfide) · Mineral Specimen / Industrial Mineral
Crystal System
Cubic (Isometric); typically occurs as cubes, pyritohedrons, or octahedrons; massive or granular habit as shown.
Mineral Group
Sulfides
Chemical Formula
FeS2
Formation Process
Found in diverse environments including magmatic segregation, hydrothermal veins, and sedimentary rocks (as authigenic nodules).
About This Crystal
Boldly metallic luster with a brassy yellow to pale gold color. Opaque with a granular, micro-crystalline surface that sparkles under light.
Physical Characteristics
Color: Brass-yellow; Streak: Greenish-black to brownish-black; Fracture: Conchoidal to uneven; Specific Gravity: 4.8–5.0; Brittle.
Optical Properties
Opaque; metallic luster; strongly reflective; lacks pleochroism and birefringence due to its cubic nature.
Hardness & Durability
Origin Region
Global distribution; notable sources include Spain (Rio Tinto), Peru (Huánuco), Italy (Elba), and the USA.
Hardness & Durability
Mohs hardness: 6 to 6.5. Harder than most sulfides; brittle tenacity; subject to 'pyrite disease' (oxidation) in high humidity.
Care & Maintenance
Keep dry to prevent oxidation (sulfuric acid production); clean with a soft dry brush; avoid water or ultrasonic cleaners.
Rarity & Value
Very common; low price range for common specimens; value increases for large, perfectly formed cubic geometric crystals.
Special Characteristics
Often called 'Fool's Gold' due to color; can show striations on crystal faces; produces sparks when struck against steel.
Lore & History
Historically used by Native Americans as mirrors; used in early firearms (wheellocks) to create sparks; associated with abundance and protection.