Name________________________
Per___
Lab # ______
IGNEOUS ROCK LAB
INTRODUCTION: Igneous rocks are always the result of the solidification of liquid
magma or lava. Only igneous rocks form from the cooling of liquid rock. Any rock can
be heated above it’s melting point (rock turns into a liquid) and then cooled back into a
solid igneous rock. Igneous Rocks are classified based on their crystal size (texture) and
color. Igneous rocks that contain large crystals indicate a slow cooling process whereas
igneous rocks with small or no crystals indicated rapid rate of cooling. Light colored
minerals are found in Felsic igneous rocks whereas dark colored minerals are found in
mafic igneous rocks.
Objective: After you have completed this lab you should be able to identify igneous rocks
based on their textures and minerals present. Use the Scheme for Igneous Rocks
identification on page 6 in the ESRT’s.
Vocabulary:
Igneous Rock-
Solidification-
Felsic-
Mafic-
Texture-
VesicularProcedure
1) Using your knowledge of Igneous Rocks, Complete the chart for each of the samples.
2) After you have completed the characteristics of the rocks, use the ESRT’s to identify
the rock.
3) Answer all the questions in Complete Sentences. If you do not answer a question or
any part or any part of the question, your lab will be returned to you without a grade.
If you do not write clearly and in complete sentences your lab will be returned to you
without a grade.
IGNEOUS ROCK LAB DATA TABLE
Station
Number
1
2
3
4
5
6
7
8
9
10
Color
(Light, Dark, Both)
Texture
Vesicular or Non
Vesicular
Minerals Present
Density
Composition
(High, Low, Med)
(Felsic, Mafic or Both)
Igneous Rock
Name
Questions (Please use your ERST’s to answer the following in complete sentences)
1. What three characteristics are used to identify igneous rocks?
2. What observations of an igneous rock would lead to the conclusion that the rock
formed slowly deep within the earth?
3. What observation of an igneous rock would to the conclusion that the rock formed on
the earth’s surface?
4. What is the difference between magma and lava, and what is the difference between
the types of igneous rocks they create?
5. How could a sedimentary or metamorphic rock be changed into an igneous rock?
6. What does Basalt and Gabbro have in common, what makes them different?
7. What does Rhyolite and Basalt have in common, what makes them different?
You do not have to answer these questions in complete sentences.
8. Name three igneous rocks that are low in density and light in color.
9. Name five igneous rocks that have coarse textures.
10. What igneous rock formed deep within the earth and is composed of quartz and
Potassium Feldspar?
11. What igneous rock formed as lava flowed into water and is mainly composed of
pyroxene and olivine?
12. What fine-grained igneous rock is composed of 60% Plagioclase Feldspar, 15%
Biotite and 25% Amphibole?