metamorphic
Quartz-rich breccia or quartzite with iron-oxide veining
Microcrystalline to granular SiO₂ (quartz), with hematite/goethite and minor feldspar or mica
AI-generated identification · may be incorrectTypically Mohs 7, white to pale gray with reddish-brown fracture veins, vitreous to sugary luster, granular crystalline texture, and no prominent cleavage; specific gravity about 2.6. The angular-looking internal fractures and iron staining suggest brecciation or vein filling.
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Physical properties
Typically Mohs 7, white to pale gray with reddish-brown fracture veins, vitreous to sugary luster, granular crystalline texture, and no prominent cleavage; specific gravity about 2.6. The angular-looking internal fractures and iron staining suggest brecciation or vein filling.
Formation & geological history
Likely formed when quartz-rich rock or silica veins were metamorphosed and fractured, followed by iron-bearing mineral deposition; age is indeterminate and depends on locality. Such material occurs in hydrothermal veins and metamorphic terrains.
Uses & applications
Used mainly as a lapidary, ornamental, or teaching specimen; attractive pieces may be polished or tumbled. It has little commodity value unless unusually patterned or gem-quality.
Geological facts
The red-brown coloration commonly comes from hematite or hydrated goethite rather than red quartz. A steel file should not scratch fresh quartz surfaces, while iron staining may rub off or weather.
Field identification & locations
Common in quartz veins, quartzite outcrops, and iron-stained metamorphic zones worldwide; test hardness, inspect for quartz grain fracture, and use dilute acid only to rule out carbonate coatings. Exact identification would require locality and thin-section or chemical testing.
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