metamorphic
Quartz vein in mica-rich host rock
Milky quartz (SiO₂) in a mica-rich metamorphic matrix, likely schist
AI-generated identification · may be incorrectMilky-white, glassy to pearly quartz occurs in a brown, flaky matrix that may contain mica; quartz hardness 7, mica about 2–3, with quartz lacking cleavage and mica splitting into sheets. The specimen appears massive and irregular rather than well-crystallized.
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Physical properties
Milky-white, glassy to pearly quartz occurs in a brown, flaky matrix that may contain mica; quartz hardness 7, mica about 2–3, with quartz lacking cleavage and mica splitting into sheets. The specimen appears massive and irregular rather than well-crystallized.
Formation & geological history
Likely formed when silica-rich fluids filled fractures in older metamorphic rock, with quartz crystallizing as the vein cooled. The image alone cannot establish its age or precise host-rock identity.
Uses & applications
Primarily a common collector specimen; quartz is also used in glass, electronics, and construction, while mica has industrial uses as an electrical and thermal insulator.
Geological facts
Quartz veins commonly form during metamorphism and hydrothermal activity, and can host other minerals. The brown matrix’s exact mineral composition is not identifiable from the photograph.
Field identification & locations
Look for white, hard quartz cutting or intergrown with a distinctly flaky, layered matrix; quartz scratches glass, while mica flakes may peel apart. Quartz veins occur in metamorphic and igneous terrains worldwide.
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