metamorphic
Weathered quartz-bearing rock, possibly gneiss or quartzite
Indeterminate; likely quartz-rich metamorphic rock containing quartz and feldspar
AI-generated identification · may be incorrectBrown-gray, coarse and irregularly textured with pale crystalline patches and a dull to weakly vitreous luster. Estimated hardness 6–7 Mohs; cleavage is poor overall, though feldspar grains may show cleavage; density approximately 2.6–2.7 g/cm³.
Identified More metamorphic →
Explore Weathered quartz-bearing rock, possibly gneiss or quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Brown-gray, coarse and irregularly textured with pale crystalline patches and a dull to weakly vitreous luster. Estimated hardness 6–7 Mohs; cleavage is poor overall, though feldspar grains may show cleavage; density approximately 2.6–2.7 g/cm³.
Formation & geological history
Likely formed by metamorphism of sandstone or felsic igneous rock, followed by surface weathering and iron staining. An exact geological age and diagnosis require a sharper image or a fresh broken surface.
Uses & applications
Common varieties are used as aggregate, landscaping stone, road material, and occasionally decorative slabs; this small weathered specimen has modest collecting value.
Geological facts
The pale patches may be quartz or feldspar, while the brown coloration commonly results from oxidized iron minerals. Stronger identification can come from a streak test, glass-scratch test, and examination of grain alignment.
Field identification & locations
Look for interlocking grains, quartz-rich pale areas, and any foliation; quartzite is typically more uniformly quartz-rich, whereas gneiss shows banding or aligned minerals. Common worldwide in metamorphic terrains; likely value is $1–$10 for an ordinary hand specimen.
More like this
