Types of Igneous Rocks
There are two main types of
ones are the rocks that are formed
the Earth's mantle.
These rocks are generally coarse
has been slow and the minerals have had a fairly long time to grow.
Such rocks are for example granite,
syenite, monzonite, diorite,
dunite and peridotite.
Yosemity granite - an intrusive igneous rock. By Larry via
can often be seen as
large boulders, which have been formed in a large pluton, then lifted,
and exposed by erosion of weaker, surrounding rock.
ones are the rocks that form
when magma erupts out of a
volcano on the Earth's surface.
These rocks are generally
the cooling is quick for them and the minerals don't get much time to
Some can have holes left behind by air or gas bubbles.
Giant's Causeway basalt - an extrusive igneous rock. By
Supermac1961 via Flickr.com
They can sometimes be seen as lava tubes, and quite often as columns
which were formed when lava cooled.
But they can also just cover the ground.