metamorphic
Tumbled pink-and-gray quartzite (probable)
Quartzite; predominantly microcrystalline quartz (SiO₂), with iron-oxide and other mineral impurities
AI-generated identification · may be incorrectHardness about 7 Mohs; gray, pink, and reddish coloration; vitreous to dull luster; massive, non-cleavable texture with conchoidal-to-uneven fracture. The rounded shape indicates tumbling and polishing.
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Physical properties
Hardness about 7 Mohs; gray, pink, and reddish coloration; vitreous to dull luster; massive, non-cleavable texture with conchoidal-to-uneven fracture. The rounded shape indicates tumbling and polishing.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized under heat and pressure, commonly during mountain building; its exact geological age depends on the parent sandstone. The pink-red tones likely reflect iron staining or minor feldspar/hematite.
Uses & applications
Used as decorative stone, aggregate, paving, building stone, and low-cost tumbled collectible material; generally unsuitable for faceted gemstones unless unusually pure and translucent.
Geological facts
Quartzite is commonly mistaken for quartz or jasper. A glass-scratch test can support identification because quartzite is harder than ordinary glass, though this may damage the specimen.
Field identification & locations
Common in metamorphic mountain belts worldwide, including Brazil, India, the United States, and Madagascar. Look for a sugary fused quartz texture and lack of obvious cleavage; laboratory testing would be needed for certainty from this photograph.
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