metamorphic
Quartz-rich rock, likely milky quartz or quartzite
Quartz (SiO₂), possibly quartzite with iron-oxide staining
AI-generated identification · may be incorrectWhite to cream, massive and granular with a vitreous-to-dull luster; Mohs hardness about 7, no obvious cleavage, conchoidal to irregular fracture, and specific gravity near 2.65. The tan-orange coloration likely comes from limonite/goethite staining or minor feldspar/clay impurities.
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Physical properties
White to cream, massive and granular with a vitreous-to-dull luster; Mohs hardness about 7, no obvious cleavage, conchoidal to irregular fracture, and specific gravity near 2.65. The tan-orange coloration likely comes from limonite/goethite staining or minor feldspar/clay impurities.
Formation & geological history
If quartzite, it formed when quartz-rich sandstone recrystallized during metamorphism, commonly during Precambrian or Paleozoic mountain-building. If weakly cemented vein quartz, it formed from silica-rich hydrothermal fluids filling fractures; the photograph cannot distinguish these confidently.
Uses & applications
Common quartzite is used as crushed stone, aggregate, paving, and occasionally building stone; attractive pieces are collected or used decoratively. It is generally not gem-grade because of its irregular shape and staining.
Geological facts
Quartz is one of Earth’s most abundant minerals and is highly resistant to weathering, commonly surviving as sand and resistant outcrops.
Field identification & locations
Scratch testing with a steel file or glass is useful: quartz should scratch glass and resist a steel knife. Look for sugary interlocking grains to confirm quartzite; visible sedimentary layering or abundant feldspar would suggest another quartz-rich rock.
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