metamorphic
Weathered iron-stained quartzite or jasper
Quartzite dominated by quartz (SiO₂), with iron oxides/hydroxides such as hematite and limonite
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; mottled gray, cream, orange-brown, and black surface with dull to slightly vitreous luster. Dense, non-cleaved, fine-grained, and resistant to scratching; the dark areas may include iron/manganese oxides or other minerals.
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Physical properties
Hardness about 6.5–7 Mohs; mottled gray, cream, orange-brown, and black surface with dull to slightly vitreous luster. Dense, non-cleaved, fine-grained, and resistant to scratching; the dark areas may include iron/manganese oxides or other minerals.
Formation & geological history
Likely formed when quartz-rich sedimentary rock recrystallized under metamorphic heat and pressure, with later weathering producing orange-brown iron staining. Exact age and locality cannot be determined from the image.
Uses & applications
Used as crushed stone, aggregate, landscaping material, and building/decorative stone; attractive pieces may be polished for cabochons or collected as lapidary specimens.
Geological facts
Quartzite commonly breaks across grains rather than around them, producing a sugary or splintery fracture. Jasper-like varieties are opaque and colored by impurities, especially iron oxides.
Field identification & locations
In the field, test a fresh edge with a steel knife: quartzite should resist scratching, while its grains remain tightly interlocked; dilute acid should not noticeably fizz. Common in metamorphic mountain belts worldwide, but this specimen’s exact identification needs a fresh surface or thin section.
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