igneous
Pyrite-rich Volcanic Rock
Iron Disulfide (FeS2) in Volcanic Matrix
Hardness: 6-6.5 (for pyrite), Color: Brassy yellow metallic specks in dark grey/greenish matrix, Luster: Metallic to dull, Crystal Structure: Cubic/Isometric, Specific Gravity: 4.9-5.2
- Hardness
- 6-6
Identified More igneous →
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Physical properties
Hardness: 6-6.5 (for pyrite), Color: Brassy yellow metallic specks in dark grey/greenish matrix, Luster: Metallic to dull, Crystal Structure: Cubic/Isometric, Specific Gravity: 4.9-5.2
Formation & geological history
Formed in hydrothermal veins or as an accessory mineral in igneous rocks, often through the cooling of sulfur-rich magma or volcanic gases. Common in Proterozoic to Cenozoic formations.
Uses & applications
Primarily a source of sulfur and sulfuric acid in industry; occasionally used in inexpensive jewelry or as a decorative specimen for collectors.
Geological facts
Often called Fool's Gold because its color can mimic real gold, though it is much harder and more brittle. It can produce sparks when struck against steel.
Field identification & locations
Check for metallic luster and cubic crystal habits on fresh surfaces. Often found near volcanic vents or in sedimentary shale beds. Common globally in mining districts.
