metamorphic
Pyrite-bearing schist (likely mica schist)
Muscovite–quartz schist with disseminated pyrite (FeS₂)
AI-generated identification · may be incorrectThe specimen is silvery-gold, glittery, and foliated, with platy mica flakes and possible brassy pyrite grains. Muscovite has Mohs hardness 2–2.5 and perfect basal cleavage; pyrite is harder (6–6.5), metallic, and brassy yellow. Exact identification is photo-based and should be confirmed by streak or testing.
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Physical properties
The specimen is silvery-gold, glittery, and foliated, with platy mica flakes and possible brassy pyrite grains. Muscovite has Mohs hardness 2–2.5 and perfect basal cleavage; pyrite is harder (6–6.5), metallic, and brassy yellow. Exact identification is photo-based and should be confirmed by streak or testing.
Formation & geological history
Formed when clay-rich sedimentary rock underwent regional metamorphism, aligning mica into foliation; pyrite crystallized during metamorphism or earlier sediment deposition. Such rocks commonly formed in Paleozoic or Precambrian mountain belts.
Uses & applications
Used mainly as a decorative or collector specimen; mica-bearing schist can be crushed as aggregate or fill, but this small piece has no practical industrial value.
Geological facts
The glitter likely comes from muscovite rather than gold. Pyrite leaves a greenish-black to brown-black streak, whereas gold leaves a yellow streak and is much softer and malleable.
Field identification & locations
Look for shiny, flexible mica sheets and strong planar layering; angular brassy grains suggest pyrite. Common settings include metamorphic belts worldwide, especially Appalachians, Alps, Scandinavia, and parts of India. A hand lens, streak test, and hardness test help distinguish it from gold.
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