There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from molten rock that cools and hardens. Sedimentary rocks form from compressed sediments like sand and shells. Metamorphic rocks were originally igneous or sedimentary rocks that were changed by heat and pressure in the earth. Examples are marble from limestone and slate from shale.

1. Kinds of Rocks
 Igneous Rocks
 Sedimentary Rocks
 Metamorphic Rocks

2. Igneous Rocks

3. 1. Igneous rocks are formed from liquid molten rock that cool slowly
and harden.
Igneous means made from fire and heat.
- Extrusive igneous rocks are
formed from lava expelled
during volcanic eruption.
They cool and harden on
the earth’s surface.
- Intrusive igneous rocks are
formed from magma which
cool or harden slowly inside
the earth.

6. Granite and basalt are used in concrete works such as roads,
sidewalks and buildings.
Granite is hard and it is
crushed into gravel.
Basalt is a black rock and it is
crushed into sand.

7. Sedimentary rocks

8. 2. Sedimentary rocks are formed from sediments such as sand,
pebbles, mud, shells and remains of dead plants and animals.
They hardened into rock due to pressure of water and weight of more
sediments.
Categories of Sedimentary
rocks
a. Clastic rocks- formed
from broken fragments of
pre- existing rocks and
minerals.
b. Chemical rocks- formed
when minerals precipitate
or solidify from a solution
like sea water or lake
water.
c. Organic rocks- formed
from accumulation of
plant and animal remains.

10. - Limestone is made from
shells of sea animals and
plants. It forms only
under water.
- Conglomerate is made of a
mixture of smooth round
stones and pebbles.

11. - Sandstone is made up of
tiny bits of sand. It is cut
into blocks and used in
walls and buildings
because it is strong and
easy to quarry.
- Shale is made from mud and
fine silt or clay. It is commonly
called mudstone.

12. Metamorphic Rocks

13. Metamorphic rocks are igneous or sedimentary rocks
changed by extreme heat and pressure.
Metamorphic means
“to have been
changed”
As a volcano pushes
its way up through
the earth, great heat
changes a
sedimentary rock into
metamorphic rock.

14. Metamorphic rocks are igneous or sedimentary rocks
changed by extreme heat and pressure.
Metamorphic means
“to have been
changed”
As a volcano pushes
its way up through
the earth, great heat
changes a
sedimentary rock into
metamorphic rock.

15. - Marble is a metamorphic rock which comes from limestone. Minerals or
impurities in the marble changes its color.
- Slate is made from shale. Slate and shale have the same colors, but they
do not look alike because of how they break. Slate breaks into smooth
flat sheets of rocks while shale breaks only into odd shapes.

16. - Quartzite comes from hard sandstone.
- Schist is made from mudstone or shale. As schist is made, some of the
minerals change to become mica which make the schist shine and
sparkle.