Set window back color, show msg, and OK button. The image above shows granite, an intrusive igneous rock. A close-up of basalt, an extrusive igneous rock.
Igneous rocks form from molten rock, called magma .
The two main types of igneous rocks reflect how quickly the magma cooled. Intrusive igneous rocks cooled slowly, deep in the earth. Their minerals have lots of time to form so the crystals are large and often beautiful. Light-colored intrusive rocks include granites, like those found in the Sierra Nevada of California. Dark-colored intrusive rocks include gabbros, which are abundant in ocean crust.