metamorphic

Quartz-rich pegmatitic rock, probably granitic gneiss

Quartz–feldspar–mica gneiss; locally pegmatitic granite

AI-generated identification · may be incorrect

Coarse, irregular interlocking quartz and feldspar with dark mica/amphibole and apparent foliation; white-gray to pink, vitreous quartz and dull feldspar. Hardness is about 6–7 Mohs, nonmetallic luster, low porosity, and weak-to-moderate cleavage mainly from feldspar and mica.

Identified September 13, 2026More metamorphic →

Explore Quartz-rich pegmatitic rock, probably granitic gneiss in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Likely formed by high-grade metamorphism of granitic or sedimentary protolith, with partial melting or pegmatitic injection; commonly Precambrian to Paleozoic, though age cannot be determined from the photograph.

Uses & applications

Used locally as crushed aggregate, dimension stone, landscaping rock, and occasionally as a decorative lapidary material; the specimen is not gem-grade.

Geological facts

The stretched, aligned mineral bands and lens-like quartz/feldspar masses distinguish gneiss from ordinary granite; pink coloration commonly reflects potassium feldspar and iron staining.

Field identification & locations

Identify it by coarse grain size, quartz-rich pale bands, pink feldspar, dark mica, and planar foliation; common in ancient continental shields and metamorphic mountain belts. A rough field specimen of this size is typically worth $5–$30, or up to about $50 if unusually attractive and provenance is documented.