metamorphic

Tumbled quartzite (likely iron-stained quartz)

Quartzite; predominantly quartz (SiO₂) with minor iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 7 Mohs; white to cream with reddish-orange mottling, vitreous to dull luster, massive granular texture, and no obvious cleavage. The smooth rounded shape indicates tumbling or natural water abrasion.

Identified September 6, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone recrystallizes under metamorphic heat and pressure; iron oxides create the red coloration. Quartzite occurs in many Precambrian to younger mountain belts, but this individual’s age and locality cannot be determined visually.

Uses & applications

Used as crushed stone, paving and durable building aggregate; attractive pieces are sold as lapidary rough or decorative tumbled stones. It has limited gemstone value unless unusually patterned or translucent.

Geological facts

Quartzite is typically harder and more resistant to weathering than its sandstone precursor. A strong scratch test against ordinary glass can help distinguish it from softer carbonate rocks.

Field identification & locations

Common in metamorphic terrains, stream gravels, and glacial deposits. Confirm by testing: it should scratch glass and show no fizz with dilute hydrochloric acid; a streak test is usually white.