metamorphic
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining
AI-generated identification · may be incorrectHardness about 7 Mohs; pale gray, cream, pink, and rusty brown; vitreous to sugary luster; interlocking granular quartz texture, generally lacking cleavage and breaking irregularly. The specimen appears rounded and weathered, with fractures and minor dark inclusions.
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Physical properties
Hardness about 7 Mohs; pale gray, cream, pink, and rusty brown; vitreous to sugary luster; interlocking granular quartz texture, generally lacking cleavage and breaking irregularly. The specimen appears rounded and weathered, with fractures and minor dark inclusions.
Formation & geological history
Formed when quartz-rich sandstone was recrystallized under heat and pressure during regional metamorphism, commonly during mountain building. Its exact geological age cannot be determined from the photograph and depends on its source terrane.
Uses & applications
Used as durable building stone, aggregate, road material, and decorative dimension stone; attractive pieces may be collected or polished, though this specimen appears mainly of modest collector interest.
Geological facts
Quartzite is typically harder and more resistant to weathering than its sandstone precursor. Iron oxides can produce the pink, tan, and reddish coloration visible here.
Field identification & locations
In the field, test whether it scratches glass and inspect for fused quartz grains rather than sand-sized grains or obvious bedding; acid should not fizz unless carbonate minerals are present. Common in metamorphic mountain belts worldwide.
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