Pumice is an example of extrusive igneous rock. The word extrusive means that the magma was forced onto the earth's surface and cooled in a matter of hours. Granite is an example of intrusive ...

This cooling can either be intrusive, where the magma pool gradually cools and the magma solidifies into an igneous rock. Alternatively, the cooling can extrusive, where the magma is cooled very ...

Magma that is ejected to the surface of Earth a volcanic eruption or at a spreading center cools very quickly, contains small crystals typically and is called an extrusive igneous rock.

Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidifies and can form extrusive igneous rocks or intrusive igneous ...

Both are igneous rocks (igneous rocks are those that have formed directly from magma-molten rock). Basalt is what’s known as an extrusive igneous rock - it is volcanic, formed from molten magma ...

It is an extrusive igneous rock comprised of feldspar and quartz, endemic to volcanic regions. Several dozen localities have been studied by geologists, each distinct with its own chemical ...

In my last column, I wrote about the locations where you can find igneous rocks that were formed from lava. The metarhyolite and metabasalt described in the column are known as extrusive rocks ...