Download Granite

Produced and Presented by
Ryan Hiscoke
The Rock Cycle
Explained
The Rock Cycle is a group of changes. Igneous rock can change
into sedimentary rock or into metamorphic rock. Sedimentary
rock can change into metamorphic rock or into igneous rock.
Metamorphic rock can change into igneous rock or sedimentary
rock.
Igneous Rock
Igneous rocks are sometimes called ‘the
mother of all rocks’ because they are the first
type of rock formed after a volcanic eruption.
Igneous rocks are formed when magma
breaks through the crust and pours lava over
the surface. When this cools it forms hard
rock known as igneous rock.
Granite is an example of an igneous rock
and the size of its crystals tells us how
quickly it cooled.
If the magma in the underground pockets
cool slowly the crystals will be large. But if
the lava above ground cools quickly small
crystals will form.
Igneous rocks are hard and always have
crystals in them. Igneous rocks never have
fossils in them because they come from
magma and anything near it would
disintegrate
Some examples of how different
types of Igneous rock were formed
Pumice Pumice rocks are igneous rocks which
were formed when lava cooled quickly above
ground. You can see where little pockets of air
had been. This rock is so light, that many
pumice rocks will
actually float in water. Pumice is actually a kind of glass and not
a mixture of minerals. Because this rock is so light, it is used
quite often as a decorative landscape stone. Ground to a powder,
it is used as an abrasive in polish compounds and in Lava soap.
Granite
Granite rocks are igneous rocks, which were
formed by slowly cooling pockets of magma that
were trapped beneath the earth's surface.
Granite is used for long lasting monuments and
for trim and decoration on buildings
Sedimentary Rock
When Rocks erode and
become washed away. The
particles are called sediment.
These little particles of
sediment are washed
downstream where they
eventually settle to the
bottom of the rivers, lakes,
and oceans. Layer after layer
of sediment is deposited on
top of each other. Over time
these layers are compressed
down more and more
through time, until the
bottom layers slowly turn
into rock.
Some examples of sedimentary
rock and their uses
Gypsum
Gypsum rocks are sedimentary rocks made up of
sulphate mineral and formed as the result of
evaporating seawater in massive prehistoric basins. It
is very soft and is used to make Plaster of Paris, casts,
melds, and wallboards.
Limestone
Limestone rocks are sedimentary rocks that are made
from the mineral calcite, which came from the beds of
evaporated seas and lakes and from sea animal shells.
This rock is used in concrete and is an excellent building
stone for humid regions.
Sandstone
Sandstone rocks are sedimentary rocks made from
small grains of the minerals quartz and feldspar. They
often form in layers as seen in this picture. They are
often used as building stones.
Metamorphic rock
Metamorphic means
‘change in form’.
Sometimes igneous and
sedimentary rocks may get
buried deep underground.
The heat and pressure of
Earth ‘cooks’ and twists
the rock. It changes into a
new type of metamorphic
rock. If you examine
metamorphic rock samples
closely, you'll see how
flattened some of the
grains in the rock are.
Some examples of how different
types of Metamorphic rock were
formed
Gneiss
These rocks may have been granite, which is
an igneous rock, but heat and pressure
changed it. You can see how the mineral
grains in the rock were flattened through
tremendous heat and pressure and are arranged in alternating
patterns.
Schist
These rocks can be formed from basalt, an
igneous rock like shale, a sedimentary rock or a
metamorphic rock like slate. Through
tremendous heat and pressure, these rocks were
transformed into this new kind of rock.