Dunite
“Pure olivine from the deep mantle”
Dunite is an ultramafic igneous rock composed of over 90% olivine, making it one of the simplest rocks by composition. It originates from Earth's upper mantle and is brought to the surface through tectonic processes, giving geologists a direct sample of the material beneath the crust.
olivine (90%+), chromite, pyroxene (minor), magnetite
Dun Mountain (New Zealand), Troodos Ophiolite (Cyprus), Twin Sisters (Washington, USA), Oman Ophiolite
6-7
Dunite may help fight climate change — when olivine weathers, it absorbs CO₂ from the atmosphere, and researchers are studying whether spreading crushed dunite could act as a carbon sink.
Test Your Knowledge
What does dunite's composition of >90% olivine tell geologists about its origin?
Related Specimens
Want to identify rocks yourself?