igneous/metamorphic (hydrothermal)
Pyrite in Quartz (Drill Core)
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions
Hardness: Quartz (7), Pyrite (6-6.5); Color: Milky white to translucent matrix with brassy metallic inclusions; Luster: Vitreous (Quartz) to Metallic (Pyrite); Crystal Structure: Trigeminal (Quartz) and Isometric (Pyrite); Specific Gravity: ~2.65 for Quartz, ~5.0 for Pyrite.
- Hardness
- Quartz (7), Pyrite (6-6
- Luster
- Vitreous (Quartz) to Metallic (Pyrite)
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Physical properties
Hardness: Quartz (7), Pyrite (6-6.5); Color: Milky white to translucent matrix with brassy metallic inclusions; Luster: Vitreous (Quartz) to Metallic (Pyrite); Crystal Structure: Trigeminal (Quartz) and Isometric (Pyrite); Specific Gravity: ~2.65 for Quartz, ~5.0 for Pyrite.
Formation & geological history
Formed through hydrothermal processes where hot, mineral-rich fluids circulate through fractures in the Earth's crust. As the fluid cools, quartz and metallic sulfides like pyrite crystallize simultaneously. This specific cylindrical shape indicates it is a 'drill core' sample extracted during mineral exploration or geotechnical drilling.
Uses & applications
Primarily used for geological surveying and mineral exploration to assess the gold-bearing potential of a site (pyrite is often associated with gold). Smaller pieces are kept as educational specimens or collector's items.
Geological facts
This specimen is a 'core sample,' a cylindrical section of rock removed by a specialized drill bit. Pyrite is famously known as 'Fool's Gold' due to its metallic luster and brassy hue, which led many prospectors to mistake it for the precious metal.
Field identification & locations
Identify in the field by its cylindrical shape (man-made), the brassy metallic flecks that do not scratch with a copper penny (Pyrite), and the hard white matrix that scratches glass (Quartz). Commonly found in mining districts in Nevada, Colorado, and Ontario.
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