metamorphic
Weathered quartz-rich rock, possibly quartzite or silicified sandstone
Quartzite (mostly SiO₂), with possible iron-oxide staining and minor feldspar/mica
AI-generated identification · may be incorrectAppears gray-tan, opaque to slightly translucent, with a dull to uneven vitreous luster and granular texture. Quartz-rich material is typically Mohs 7, lacks cleavage, and has specific gravity near 2.65; the image alone cannot confirm exact composition.
Identified More metamorphic →
Explore Weathered quartz-rich rock, possibly quartzite or silicified sandstone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Appears gray-tan, opaque to slightly translucent, with a dull to uneven vitreous luster and granular texture. Quartz-rich material is typically Mohs 7, lacks cleavage, and has specific gravity near 2.65; the image alone cannot confirm exact composition.
Formation & geological history
Likely formed by metamorphism or silica cementation of a quartz-rich sediment, with later weathering and iron-oxide alteration. Such rocks commonly formed in Precambrian to Paleozoic terrains, though age is not determinable visually.
Uses & applications
Used as crushed aggregate, road stone, building/decorative stone, and occasionally as a lapidary material. This irregular weathered piece has little jewelry value.
Geological facts
The rusty brown patches are likely limonite/goethite coatings or inclusions. A true quartzite usually breaks across grains rather than around them and resists scratching by steel.
Field identification & locations
Common in metamorphic belts and quartz-rich sedimentary formations worldwide, including India, Brazil, the United States, and South Africa. Confirm by testing hardness, streak, acid reaction, and grain boundaries.
More like this
