igneous
Granite-like rounded cobble
Probably granitic rock, composed mainly of quartz, feldspar, and dark mafic minerals; exact identification is uncertain from the photograph.
AI-generated identification · may be incorrectGray, fine- to medium-grained, dull, and strongly weathered, with scattered dark mineral patches. Likely hardness about 6–7 Mohs, no obvious cleavage at specimen scale, and moderate-to-high density (~2.6–2.8 g/cm³).
Identified More igneous →
Explore Granite-like rounded cobble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray, fine- to medium-grained, dull, and strongly weathered, with scattered dark mineral patches. Likely hardness about 6–7 Mohs, no obvious cleavage at specimen scale, and moderate-to-high density (~2.6–2.8 g/cm³).
Formation & geological history
Likely an intrusive igneous rock formed by slow cooling of magma deep underground, commonly Precambrian to Mesozoic in age, then rounded by stream or surface transport and weathering.
Uses & applications
Used as aggregate, road stone, building stone, and occasionally as a decorative or polishing material; this weathered cobble has little gem or collector value.
Geological facts
The rounded shape indicates abrasion during transport or prolonged weathering. The dark areas may be biotite, amphibole, or weathered mafic inclusions rather than fossils.
Field identification & locations
Commonly identified by visible interlocking quartz and feldspar grains and a speckled texture; a fresh broken surface, hand lens, and hardness testing would help distinguish granite from granodiorite or gneiss. The Ethiopian location is geologically plausible for granitic basement and transported cobbles.
