metamorphic
Quartz-rich breccia or silicified rock
Microcrystalline quartz (SiO₂) with iron-oxide staining and darker host-rock fragments
AI-generated identification · may be incorrectHardness about 7 where quartz-rich; white to translucent gray with brown-red iron staining, vitreous to dull luster, and irregular fracture rather than cleavage. The angular brown fragments cemented by white silica suggest brecciation.
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Physical properties
Hardness about 7 where quartz-rich; white to translucent gray with brown-red iron staining, vitreous to dull luster, and irregular fracture rather than cleavage. The angular brown fragments cemented by white silica suggest brecciation.
Formation & geological history
Likely formed when silica-rich fluids filled fractures and cemented broken rock, with later oxidation producing the brown coloration; age cannot be determined from the photograph. Such material occurs in hydrothermal veins, fault zones, and weathered silicified rocks.
Uses & applications
Used mainly as a lapidary, ornamental, or educational specimen; attractive pieces may be polished, but it has little industrial value compared with pure quartz or engineered aggregate.
Geological facts
The translucent edges and glassy white patches are consistent with quartz or chalcedony, while brown areas may be limonite/goethite staining. Exact identification would benefit from a fresh surface, hardness test, and acid test.
Field identification & locations
Common in hydrothermal districts and faulted volcanic or sedimentary terrains worldwide. It should scratch glass, resist steel, and show no fizz with dilute hydrochloric acid unless carbonate minerals are present.
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