The three rock groups
There are lots of different kinds of rock, with
different mixtures of minerals. But they fall into
just three groups of rock:
 Sedimentary
 Igneous
 metamorphic
Sedimentary Rock
 forms when particles of minerals which were
eroded from rock in one place get stuck together
again in another place to form a new rock
 Different sediments give different types of
sedimentary rock like for example:
 a sediment of mud gives mudstone
 A sediment of sand gives sandstone
 A sediment of shells that pile up on the ocean floor
gives limestone
Igneous rock
This forms when rock melts then cools and
hardens again.
 Magma
 Granite
 basalt
Metamorphic rock
O This rock which has been changed
underground without melting
DO “YOUR TURN”
Assignment
Marvelous marble
There isn’t much marble in the UK because
most of the limestone deposits were not
subjected to enough pressure. It is imported
from other countries. Find out why marble is
useful. Collect images of different kinds of
marble, to make a slideshow.