Igneous rocks

Rocks do not have a definite composition of mineral constituents. Feldspar and quartz are the most common minerals found in rocks. There are many different kinds of rocks which are grouped under three families on the basis of their mode of formation.

Trap rock is a construction industry term for dark-colored igneous rocks such as basalt, gabbro, and diabase that are used to make crushed stone.

Illustrated overview and examples of igneous rocks: basalt, granite, obsidian, pumice, gabbro, porphyry...

Photographs and descriptions of intrusive and extrusive igneous rocks with photos and links to detailed articles by Geology.com

Learn about igneous rocks in geology, including their origin, properties, and classification. Get examples and identification tips.

Igneous rocks are formed from rising magma, make up the vast majority of the Earth's crust, and tell us a great deal about the Earth's mantle.

Rhyolite is an extrusive igneous rock formed during eruptions of granitic magma. Pumice, obsidian, and tuff are associated rock types.