metamorphic

Quartzite

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness about 7 Mohs; rough, massive specimen with pink, tan, and rusty-brown coloration, likely from iron staining. Typically has a glassy-to-dull luster and interlocking quartz grains; no prominent cleavage.

Identified September 29, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone is metamorphosed by heat and pressure, welding its grains together. It can be Precambrian or younger; this specimen’s age cannot be determined from the image.

Uses & applications

Used as building and paving stone, crushed aggregate, and decorative stone; attractive pieces may be collected.

Geological facts

Quartzite is generally harder and more resistant to weathering than its sandstone precursor.

Field identification & locations

Look for a hard, quartz-rich rock whose grains are tightly interlocked; it often breaks across grains rather than around them. Common in metamorphic mountain belts worldwide; iron oxides can create pink or rusty tones.