metamorphic

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, with minor feldspar and iron-oxide staining

AI-generated identification · may be incorrect

Typically Mohs hardness 7, white to gray or tan, with a glassy to sugary luster and interlocking quartz crystals; massive, with no obvious cleavage and specific gravity about 2.6–2.7. The rounded, weathered specimen appears quartz-rich, though the photograph cannot confirm exact identity.

Identified September 15, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone was deeply buried and recrystallized during metamorphism, commonly during mountain-building; its age depends on the original sandstone and regional geology. Common in metamorphic belts and resistant ridges worldwide.

Uses & applications

Used as crushed stone, aggregate, road material, dimension stone, and decorative landscaping rock; attractive pieces may be polished or collected. Ordinary hand specimens generally have modest value.

Geological facts

Quartzite is more resistant than its sandstone precursor and commonly forms prominent ridges or ledges. Iron oxides can produce the yellow-brown patches visible here.

Field identification & locations

In the field, quartzite is hard enough to scratch glass, commonly breaks across grains rather than around them, and does not fizz with dilute hydrochloric acid unless carbonate cement is present; it may be confused with quartz or silicified rock. Common localities include the Appalachians, Rocky Mountains, India, Brazil, and Scandinavia.