igneous
Worn granitic or quartz-rich rock fragment
Likely granite or granitic gneiss; exact identification requires a fresh surface and testing
AI-generated identification · may be incorrectGray-beige, fine- to medium-grained, dull to weakly sparkling surface with probable quartz and feldspar; hardness about 6–7 Mohs, no obvious cleavage, and moderate-to-high density. The rounded shape indicates water or sediment abrasion.
Identified More igneous →
Explore Worn granitic or quartz-rich rock fragment in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-beige, fine- to medium-grained, dull to weakly sparkling surface with probable quartz and feldspar; hardness about 6–7 Mohs, no obvious cleavage, and moderate-to-high density. The rounded shape indicates water or sediment abrasion.
Formation & geological history
Most likely an eroded fragment of ancient continental igneous rock, formed by slow cooling of silica-rich magma deep underground; comparable rocks commonly range from Precambrian to younger ages. The image alone cannot establish its precise age or whether it is gneiss.
Uses & applications
Unlikely to have commercial value at this size; similar granite is used for aggregate, building stone, countertops, monuments, and landscaping. Collecting value is generally negligible unless locality or texture is distinctive.
Geological facts
Visible speckling may represent quartz, feldspar, and dark mica or amphibole. A streak, acid reaction, magnetism test, and inspection of a broken face would improve identification.
Field identification & locations
Common in stream gravels, glacial deposits, road cuts, and weathered bedrock, especially in continental and mountainous regions. Look for interlocking grains; granite is typically nonlayered, while gneiss shows mineral banding.
