Pyrite in Quartz
FeS2 (Iron Pyrite) with SiO2 (Quartz)
Rock Type: Mineral/Igneous/Hydrothermal

Physical Properties
Pyrite: Hardness 6-6.5, brass-yellow color, metallic luster, cubic crystal structure. Quartz: Hardness 7, can be massive or crystalline, often white, clear, or iron-stained (orange/brown).
Formation & Geological History
Formed in hydrothermal veins or as replacement deposits. Often associated with other sulfide minerals and gold.
Uses & Applications
Historically used for making sparks to start fires. Extracted for sulfur or iron ore. Often collected by mineral enthusiasts. 'Fool's gold' due to its appearance.
Geological Facts
Pyrite is the most common of the sulfide minerals. The name comes from the Greek word 'pyr' meaning fire, as it creates sparks when struck against metal or hard stone.
Field Identification & Locations
Identify by its brassy color, metallic luster, and hardness (scratches glass). Unlike gold, pyrite is brittle and leaves a greenish-black streak. Commonly found worldwide in various geological settings.
Identified on: 4/26/2026
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