There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from cooled magma and are categorized as either extrusive or intrusive based on if they cool above or below ground. Sedimentary rocks form from the compaction and cementation of sediments and sometimes contain fossils. Metamorphic rocks form from changes to existing igneous or sedimentary rocks through heat and pressure, creating new rock types with interlocking crystals. The document provides examples and characteristics of each rock type.

1. TYPES OF ROCKS
GRADE 10 GEOGRAPHY
PRESENTED BY MR MS NTOMBELA
216017497

2. AT THE END OF THE LESSON
LEARNERS SHOULD BE ABLE TO:
 Name three(3) types of rocks.
 Know the characteristics of each type of rock.
 Distinguish the rock type through the example.

3. THREE(3) TYPES OF ROCKS

4. IGNEOUS ROCK
Extrusive
Rocks that are from the cooled magma
(above the ground).
They cooled more quicker, therefore
formed small crystals.
The examples: basalt, obsidian,
andesite, pumice, rhyolite and scoria.

5. CONTINUES…
Intrusive
Rocks that are from cooled magma(below
ground).
They cooled very slow so formed large
crystals.
The slow cooling allows minerals to
collect.
The examples: granite, pegmatite; diorite
and gabbro.

6. SEDIMENTARY ROCKS
They are made up of smaller rocks
cemented together.
Sometimes have fossils.
Usually have layers.

7. CONTINUES…
 Forms when loose materials(rocks, sand) deposited by water and wind, is
compacted and cemented together.
 Forms as the chemical reaction in water that leave the chemical deposit,
usually in the ocean floor.
 It forms along rivers, lakes or under the water in the rivers and lakes.
 Examples: sandstone, conglomerate, siltstone, shale and limestone

8. METAMORPHIC ROCK
Forms when igneous, sedimentary and
other metamorphic rocks heated or
squished, forming a new rock type.
Usually have the interlocking crystals and
layers called foliation.
Examples: marble, slate, gneiss and schist.

9. CONTINUES…
The formation can either happen
underground or above the ground.
• Underground – high pressure and heat
• Above ground – volcano erupting.
When classifying them, they always differ from
the parent rock.

10. REFERENCES
Barth, T. F. W. (2007). Quartzite. In: McGraw Hill Encyclopedia of Science & Technology, 10th Edition. McGraw-
Hill. Volume 14. 722.
http://www.sandatlas.org/rock-types/
https://www.slideshare.net/SameerNK/types-of-rock-32644319
https://www.slideshare.net/enolen/types-of-rocks-1574521
https://www.slideshare.net/junheldalanon/rock-types?qid=c2a87d03-d81a-42c5-b9ba-
0db42fa2dfd8&v=&b=&from_search=9
https://www.slideshare.net/kristinvoolstra/types-of-rock