Rock Topics

Common Igneous Rocks (Part 3)

Diorite

Diorite is a medium-colored (or intermediate), phaneritic igneous rock.   This sample is composed of light-colored orthoclase feldspar and quartz crystals and dark-colored hornblende. 

Diorite
Diorite (Photograph by Parvinder Sethi)

Peridotite

Peridotite is a phaneritic, mafic igneous rock.   This sample is composed entirely of olivine.

Peridotite
Peridotite (Photograph by Parvinder Sethi)