igneous
Polished dark-speckled igneous pebble, likely diorite or gabbro
Probable diorite (plagioclase feldspar and hornblende/biotite); exact identification is uncertain from the image
AI-generated identification · may be incorrectCoarse black-and-cream speckling suggests interlocking light feldspar and dark mafic minerals. Typical hardness is about 6–7 Mohs, with a granular crystalline texture; the glossy surface appears polished, and the pale patch may be a feldspar-rich area or a natural vein.
Identified More igneous →
Explore Polished dark-speckled igneous pebble, likely diorite or gabbro in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse black-and-cream speckling suggests interlocking light feldspar and dark mafic minerals. Typical hardness is about 6–7 Mohs, with a granular crystalline texture; the glossy surface appears polished, and the pale patch may be a feldspar-rich area or a natural vein.
Formation & geological history
Likely crystallized slowly from magma underground, forming an intrusive igneous rock. Its age and precise formation environment cannot be determined from the photograph.
Uses & applications
Diorite and gabbro are used as crushed stone, aggregate, and sometimes decorative building stone; this small polished pebble is mainly suitable for collecting or display.
Geological facts
Diorite is an intermediate-composition intrusive rock, while gabbro is darker and more mafic; both can show contrasting light and dark mineral grains.
Field identification & locations
The visible coarse, interlocking grains support an intrusive-rock identification, but a fresh surface and mineral tests would help distinguish diorite from gabbro or another dark igneous rock. Such rocks occur worldwide in ancient continental crust and igneous intrusions.
