Pyrite on Matrix
Pyrite (Iron Disulfide) · Mineral Specimen
Crystal System
Cubic (Isometric); commonly occurs as cubes, pyritohedrons, or in this granular/drusy habit
Mineral Group
Sulfides
Chemical Formula
FeS2
Formation Process
Hydrothermal or sedimentary; forms via iron-rich fluids interacting with sulfur in reduced oxygen environments.
About This Crystal
This specimen features a dense coating of tiny, glittering metallic crystals (druzy pyrite) on a dark, possibly limonite or shale matrix. The pyrite exhibits a pale brassy-yellow color with a high metallic luster, while white patches suggest secondary mineral coatings like calcite or gypsum.
Physical Characteristics
Color: Brass-yellow; Streak: Greenish-black to brownish-black; Luster: Metallic; Tenacity: Brittle; Magnetism: Weakly magnetic after heating.
Optical Properties
Opaque; lacks transparency. No birefringence or pleochroism due to cubic structure and metallic nature.
Hardness & Durability
Origin Region
Global; notable sources include Peru, Spain, and Italy. Common in sedimentary and hydrothermal environments.
Hardness & Durability
Mohs Hardness: 6.0–6.5. Brittle with a conchoidal to uneven fracture. Sensitive to high humidity (Pyrite Disease).
Care & Maintenance
Keep dry; humidity can cause oxidation into iron sulfates. Clean only with a soft brush or compressed air; avoid water or ultrasonic cleaners.
Rarity & Value
Common mineral but aesthetically pleasing as a druzy specimen. Low to moderate value depending on crystal definition and matrix contrast ($10–$50 for this size).
Special Characteristics
Features a 'drusy' habit with high surface reflectivity; may show 'Fool\'s Gold' metallic flash under direct light.
Lore & History
Historically used for fire-starting (ancient Greek 'pyr' for fire). Traditionally associated with the Solar Plexus chakra, representing abundance, protection, and willpower.