1. Igneous Rocks
Eric Angat
Teacher

2. Identifying Rocks

3. How do I identify an igneous rock?
Essential Question
How do I identify an igneous rock?

4. Instructions
Answer the clarifying questions individually (20 minutes).
When done in answering all 15 questions, your teacher will tell you to group yourselves together and then distribute the bags of igneous rocks.
2. Read and follow the instructions. Talking too much deprives you and others of needed learning so you need to be quiet and focus on the task at hand. You will receive a consequence such as detention or ISS if you do not follow instructions.
3. Observe each rock and record your observations on your activity papers.

6. Extrusive igneous rock-on the surface
Felsic Igneous rock
Mafic
Igneous rock
Small
Crystals
Extrusive igneous rock-on the surface
Intrusive igneous rock-
( pluton) underground
Big
Crystals

7. 1. What is rock texture?
The texture of a rock refers to its grain or mineral crystal size.
MIXED FINE AND COARSE
Big crystals
Small crystals
Mica=black
Feldspar=brown
Quartz=white
Porphyritic texture
Coarse texture
Fine texture

8. 1. What is rock texture?
The texture of a rock refers to its grain or crystal size.
Breccia-mixture of large and small grains.
Very small crystals
Big pores or holes.
Pyroclastic
texture
Glassy texture
Vesicular texture

9. Breccia-mixture of large and small grains.
MIXED FINE AND COARSE
Breccia-mixture of large and small grains.
Porphyritic texture
Pyroclastic
texture

10. 2. How do Igneous rocks form?
Extrusive rocks- example is basalt.
Intrusive rocks- example is granite.

11. 3. What are the types of Igneous Rocks

12. 4. How do igneous rocks form from subduction?
1.Oceanic
lithosphere
sinks to the
asthenosphere.
3.Lava cools to become extrusive rocks.
volcanoes
2.Magma cools to become intrusive rocks.
Plate melts to become magma.
subduction

13. To compare relative sizes

14. 5. The parent material for all rocks is
A. silica B. quartz C. granite D. magma

15. 6. Which of the following types of rock is produced by magma that cools deep below the earth's crust?
A. extrusive igneous B. intrusive igneous C. foliated metamorphic D. chemical sedimentary

16. 7.The size and arrangement of crystal grains in igneous rocks is called
A. density B. texture C. hardness D. luster

17. 8.The texture of igneous rock is determined by the rate at which magma
A. flows from a volcano B. cools C. melts D. compresses
Slow cooling =big crystals
Fast cooling=small crystals

18. 9. An igneous rock with a mixture of large and small grains is
A. a porphyry B. an intrusion C. an extrusion D. a breccia

19. dark colored and has big crystals.
10. An igneous rock that is
dark colored and has big
crystals.
Felsic, intrusive, fine crystals
Mafic, extrusive, coarse grain
Mafic, intrusive, coarse grain
Felsic, extrusive, fine grain

20. What is the Rock Cycle?