metamorphic
Quartz-bearing altered rock
Likely quartz vein in weathered schist or gneiss; quartz is SiO₂
AI-generated identification · may be incorrectVisible milky-gray quartz occurs with brown iron-oxide staining and darker foliated material, suggesting mica-rich host rock. Quartz hardness is 7, vitreous luster, trigonal structure, and no cleavage; the host appears finer-grained and foliated.
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Physical properties
Visible milky-gray quartz occurs with brown iron-oxide staining and darker foliated material, suggesting mica-rich host rock. Quartz hardness is 7, vitreous luster, trigonal structure, and no cleavage; the host appears finer-grained and foliated.
Formation & geological history
Probably formed when silica-rich hydrothermal fluids filled fractures in older metamorphic rock, followed by weathering and oxidation near the surface. Exact age and locality cannot be determined from the photograph.
Uses & applications
Common quartz-bearing rock has little industrial value unless exceptionally pure; quartz may be used for glass, aggregate, or mineral specimens. Attractive pieces can be sold as field specimens.
Geological facts
Brown-red coloration commonly comes from limonite/goethite after oxidation of iron-bearing minerals. The irregular white zones and rusty seams are characteristic of quartz veining rather than a single homogeneous mineral.
Field identification & locations
Look for glassy translucent white-gray quartz cutting across darker foliated host rock, hardness sufficient to scratch ordinary glass, and rusty staining. Common in metamorphic terrains and hydrothermal vein districts worldwide.
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