metamorphic
Weathered quartz-rich rock, likely quartzite
Quartzite (mostly microcrystalline SiO₂), possibly quartz-rich sandstone
AI-generated identification · may be incorrectPale cream to gray, dull-to-slightly sparkly luster, granular texture, and no obvious cleavage; quartzite has Mohs hardness about 7 and specific gravity around 2.6–2.7. The rounded shape indicates natural stream or beach abrasion.
Identified More metamorphic →
Explore Weathered quartz-rich rock, likely quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Pale cream to gray, dull-to-slightly sparkly luster, granular texture, and no obvious cleavage; quartzite has Mohs hardness about 7 and specific gravity around 2.6–2.7. The rounded shape indicates natural stream or beach abrasion.
Formation & geological history
Quartzite forms when quartz-rich sandstone is compacted and recrystallized during metamorphism, commonly during mountain-building; its exact age cannot be determined from the photograph. If it is sandstone instead, it formed by sediment accumulation and cementation.
Uses & applications
Used as crushed stone, road aggregate, building stone, landscaping rock, and occasionally decorative material; this small specimen has little commercial value.
Geological facts
Quartz-rich rocks resist weathering, so they commonly persist as rounded cobbles after softer surrounding rocks erode.
Field identification & locations
Look for quartz grains fused into an interlocking, hard mass that scratches glass and does not fizz with dilute hydrochloric acid. Common in metamorphic belts and gravel deposits; an unpolished hand specimen is typically worth $1–$10.
More like this
