metamorphic
Milky quartz-bearing rock, possibly quartzite
Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix
AI-generated identification · may be incorrectWhite to translucent, granular crystalline texture with a vitreous to sugary luster; quartz hardness is Mohs 7, lacks cleavage, and has conchoidal fracture. The dark specks may be mica, graphite, or another accessory mineral; exact identification requires testing.
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Physical properties
White to translucent, granular crystalline texture with a vitreous to sugary luster; quartz hardness is Mohs 7, lacks cleavage, and has conchoidal fracture. The dark specks may be mica, graphite, or another accessory mineral; exact identification requires testing.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized during metamorphism, generally from Precambrian to younger mountain-building events. A massive quartz vein is an alternative possibility based on the limited view.
Uses & applications
Used as crushed aggregate, landscaping stone, refractory material, and silica source; attractive pieces may be collected or polished, though this specimen appears mainly of modest educational value.
Geological facts
Quartz is one of Earth’s most abundant minerals and commonly develops interlocking grains during quartzite formation. Its white color results from microscopic fluid inclusions, fractures, or impurities.
Field identification & locations
Common in metamorphic terrains and quartz veins worldwide, including the Appalachian Mountains, Alps, Brazil, India, and Australia. A glassy streakless surface, hardness greater than steel, and no reaction to dilute acid support quartz; acid and hardness tests should be performed inconspicuously.
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