Pyrite with Quartz
Pyrite var. Iron Disulfide on Quartz (Silicon Dioxide) · Mineral Specimen / Collector Mineral
Crystal System
Pyrite: Cubic (Isometric), commonly as cubes or pyritohedrons; Quartz: Trigonal, commonly as hexagonal prisms.
Mineral Group
Pyrite: Sulfides (Pyrite Group); Quartz: Silicates (Tectosilicate)
Chemical Formula
FeS2 (Pyrite) + SiO2 (Quartz)
Formation Process
Primarily hydrothermal precipitation in mineral veins at high to moderate temperatures, often associated with other sulfidic ores and silica-rich fluids.
About This Crystal
Features brassy, metallic gold-colored Pyrite crystals with a strong metallic luster, resting on a matrix of translucent to white, druzy quartz crystals with vitreous luster.
Physical Characteristics
Pyrite: Brass-yellow color, greenish-black streak, 4.9-5.2 SG, conchoidal fracture. Quartz: Colorless to white, white streak, 2.65 SG, conchoidal fracture. Brittle tenacity.
Optical Properties
Pyrite: Opaque, metallic luster, no pleochroism. Quartz: Transparent to translucent, vitreous luster, uniaxial (+) with low birefringence.
Hardness & Durability
Origin Region
Prominent sources include Peru (Huanzala), Spain (Navajun), and the USA; forms in hydrothermal veins and sedimentary environments.
Hardness & Durability
Pyrite: 6.0–6.5 Mohs (brittle). Quartz: 7.0 Mohs. Pyrite is susceptible to 'pyrite disease' (oxidation) in high humidity.
Care & Maintenance
Keep in a dry, low-humidity environment to prevent oxidation (sulfuric acid production). Clean with a soft dry brush; avoid ultrasonic cleaners or prolonged water exposure.
Rarity & Value
Common as individual species, but aesthetic combination specimens like this are highly valued by collectors. Values range from $20 to several hundred dollars based on crystal perfection.
Special Characteristics
Striated crystal faces on the pyrite; metallic luster contrast against the druzy quartz matrix. Pyrite can exhibit paramagnetism after heating.
Lore & History
Known as 'Fool's Gold' for its resemblance to precious metals. Historically used by Native Americans as mirrors. Traditionally associated with the solar plexus chakra, abundance, and protection.