metamorphic
Quartz-veined altered rock
Likely quartz-bearing metasediment or altered igneous rock; vein mineral: quartz (SiO₂)
AI-generated identification · may be incorrectTan, weathered host rock cut by a white, massive quartz vein, with possible iron-oxide staining and minor mica/clay minerals. Quartz has Mohs hardness 7, vitreous luster, no cleavage, and a specific gravity near 2.65; the host is softer and compositionally uncertain.
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Physical properties
Tan, weathered host rock cut by a white, massive quartz vein, with possible iron-oxide staining and minor mica/clay minerals. Quartz has Mohs hardness 7, vitreous luster, no cleavage, and a specific gravity near 2.65; the host is softer and compositionally uncertain.
Formation & geological history
Formed when silica-rich hydrothermal fluids filled a fracture, depositing quartz and altering the surrounding rock. The vein age cannot be determined from the image and depends on the host rock’s geological history.
Uses & applications
Primarily a collecting or teaching specimen; quartz-veined rock may be used decoratively, but this small piece has little industrial or jewelry value unless the vein contains attractive crystals or ore minerals.
Geological facts
The sharp white band is characteristic of vein quartz rather than a separate sedimentary layer. Red-brown patches commonly indicate oxidation of iron-bearing minerals such as pyrite or biotite.
Field identification & locations
Look for the white vein cutting across the host, glassy quartz fragments, hardness sufficient to scratch glass, and lack of fizz with dilute acid. Common in hydrothermal terrains worldwide, including granite, volcanic, and metamorphic regions.
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