metamorphic
Banded quartzite pebble
Quartzite, predominantly microcrystalline quartz (SiO₂), with a pale quartz vein or relict sedimentary band
AI-generated identification · may be incorrectHardness about 7 Mohs; gray-brown, fine-grained, dull to weakly vitreous surface, massive texture, and no obvious cleavage. The contrasting white band is likely quartz-rich material; density is typically 2.6–2.7 g/cm³.
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Physical properties
Hardness about 7 Mohs; gray-brown, fine-grained, dull to weakly vitreous surface, massive texture, and no obvious cleavage. The contrasting white band is likely quartz-rich material; density is typically 2.6–2.7 g/cm³.
Formation & geological history
Formed when quartz-rich sandstone was recrystallized under heat and pressure, commonly during regional metamorphism; the white band may be a later quartz vein. Exact geological age cannot be determined from the photograph.
Uses & applications
Used as durable aggregate, building stone, landscaping material, and occasionally as a decorative or lapidary stone. This rounded specimen has modest collector value.
Geological facts
Quartzite is generally tougher and more resistant to weathering than its sandstone precursor. A fresh broken surface often shows interlocking quartz grains and can scratch ordinary glass.
Field identification & locations
Common in metamorphic mountain belts and river or beach gravels derived from them. Confirm with a glass-scratch test, absence of fizz in dilute acid, and inspection for interlocking quartz grains; the image alone cannot exclude a silicified sandstone or chert.
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