mineral
Pyrite-bearing sulfide ore specimen
Pyrite (iron disulfide, FeS₂), likely with other metallic sulfides and host rock
AI-generated identification · may be incorrectBrassy yellow to silvery metallic luster, granular/massive texture, and no clearly visible crystal form in this fragment; pyrite hardness is 6–6.5 Mohs, specific gravity about 5.0, with poor cleavage. The dark matrix and irregular metallic grains suggest an ore specimen rather than pure pyrite.
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Physical properties
Brassy yellow to silvery metallic luster, granular/massive texture, and no clearly visible crystal form in this fragment; pyrite hardness is 6–6.5 Mohs, specific gravity about 5.0, with poor cleavage. The dark matrix and irregular metallic grains suggest an ore specimen rather than pure pyrite.
Formation & geological history
Forms in hydrothermal veins, sedimentary rocks, and metamorphic environments when sulfur-rich fluids react with iron; specimens may range from ancient Precambrian ores to much younger deposits. Exact age and locality cannot be determined from the photograph.
Uses & applications
Pyrite is mined as a sulfur source and occasionally for iron, though it is mostly a collector mineral; associated sulfides may contain copper, lead, zinc, silver, or gold. Attractive pieces are sold as mineral specimens and can be polished, but pyrite is unsuitable for ordinary jewelry because it tarnishes and oxidizes.
Geological facts
Often called “fool’s gold,” pyrite is typically harder and more brittle than gold and commonly forms cubic crystals or striated masses. Oxidation can produce acidic drainage and yellow-brown iron sulfate coatings.
Field identification & locations
Identify by its brass-yellow metallic color, high density, brittleness, and ability to mark unglazed porcelain dark green-black; gold is softer and leaves a yellow streak. Common localities include Peru, Spain, Italy, China, the United States, and Canada.
