Pyrite
Pyrite · Mineral Specimen / Industrial Mineral / Semi-Precious Gemstone
Crystal System
Cubic (Isometric); habit is typically cubic, octahedral, or pyritohedral, but this specimen shows a massive, granular, or microcrystalline habit.
Mineral Group
Sulfides
Chemical Formula
FeS2
Formation Process
Primarily Hydrothermal or Magmatic crystallization, but also forms via Sedimentary precipitation in anaerobic conditions and Metamorphic processes.
About This Crystal
A brassy-yellow mineral with a strong metallic luster. This specimen appears as an aggregate of tiny, interlocked micro-crystals (granular habit). It is opaque with a pale brass-yellow color and reflects light from numerous small crystal facets.
Physical Characteristics
Color: pale brass-yellow; Streak: greenish-black to brownish-black; Cleavage: poor/indistinct; Fracture: conchoidal to uneven; Specific Gravity: 4.9–5.2; Tenacity: brittle; Magnetism: weak after heating; Fluorescence: none.
Optical Properties
Opaque; metallic luster; shows no pleochroism or birefringence as it is isotropic (cubic system). High reflectivity.
Hardness & Durability
Origin Region
Globally distributed; notable sources include Spain (Rio Tinto), Peru (Huaron), Italy (Elba), and the USA (Arizona, Colorado, Pennsylvania). Found in hydrothermal veins and sedimentary environments.
Hardness & Durability
Mohs hardness: 6–6.5. Hard enough to scratch glass. Toughness is brittle, making it prone to shattering on impact. Stability: reactive under high humidity (can oxidize to sulfuric acid and iron oxides).
Care & Maintenance
Keep in a dry, low-humidity environment to prevent 'pyrite disease' (oxidation). Clean only with a dry cloth or soft brush; avoid water and chemicals. Store separately to prevent scratching softer stones.
Rarity & Value
Common. Generally low value as a mineral specimen unless found in perfect large cubic formations. Treatments are rare, though it is sometimes stabilized with resins.
Special Characteristics
Known as 'Fool's Gold' due to its metallic yellow appearance. It is a semiconductor and can exhibit thermoelectric properties (piezoelectric and pyroelectric effects).
Lore & History
Historically used by Native Americans for mirrors and as a spark-generator for starting fires (its name comes from the Greek 'pyr' for fire). In traditional lore, it is associated with the Solar Plexus chakra and is believed to symbolize wealth, prosperity, and willpower.