igneous
Quartz-rich pegmatite or weathered granite
Leucocratic granitic rock, chiefly quartz (SiO₂), feldspar, and minor mica/iron oxides
AI-generated identification · may be incorrectWhite to pale gray, coarse-grained and granular with glassy quartz and chalky/weathered feldspar; hardness about 6–7 overall, vitreous to dull luster, no consistent cleavage as a rock, specific gravity roughly 2.6–2.7.
Identified More igneous →
Explore Quartz-rich pegmatite or weathered granite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
White to pale gray, coarse-grained and granular with glassy quartz and chalky/weathered feldspar; hardness about 6–7 overall, vitreous to dull luster, no consistent cleavage as a rock, specific gravity roughly 2.6–2.7.
Formation & geological history
Formed by slow cooling of silica-rich magma, likely as granite or pegmatite; the rusty stains and friable surface indicate later weathering. Its exact geological age cannot be determined from the photograph.
Uses & applications
Commonly used as aggregate, landscaping stone, and occasionally decorative material; unattractive pieces have little jewelry value.
Geological facts
The specimen appears to contain abundant white feldspar or quartz, with scattered dark mica or iron-oxide grains. A close inspection or acid and hardness tests would distinguish it from limestone or quartzite.
Field identification & locations
Common in continental crust and found in granitic terrains worldwide. Quartz scratches glass, while feldspar commonly shows cleavage; dilute hydrochloric acid should not noticeably fizz if it is granite or pegmatite.
