Name________________________________________Date_____________________Period_____
Rock Identification Lab
Igneous Rocks
Directions: Using the rocks – answer the questions and fill in the table below!
1. Look at the rock samples and using your notes or reference table and the definition of extrusive and
intrusive igneous rocks.
List the rock numbers that could be intrusive:
List the rock numbers that could be extrusive:
2. How did you determine which were intrusive and which were extrusive?
3. Which rock has a glassy appearance? And what does this mean about the rate at which it cooled?
4. Which rock will float in water? Explain how this is possible?
5. Using the chart below, identify the seven (7) igneous rocks. Write the correct number in the blank
provided. Have your teacher check your table and initial the correct answers:
Rock #
Characteristics
Obsidian
Granite
Fine Grained
Contain Quartz
*****
Has gas pockets (vesicular)
Basalt
Pumice
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
Large crystals in fine
Floats in Water
Porphyry
*****
Dark Minerals
Light Minerals
Gabbro
*****
Course Grained
Glassy
Rhyolite
*****
*****
Name________________________________________Date_____________________Period_____
Rock Identification Lab
Analysis and Conclusion:
1. On what two characteristics are the igneous rocks classified?
2. How is it possible to determine the cooling rate of an igneous rock? Explain your answer.
Use the Reference Tables provided to answer questions 3-13.
3. What minerals tend to make up the lighter colored igneous rocks?
4. What minerals tend to make up the darker colored igneous rocks?
5. Based on the reference table, what are the characteristics of felsic igneous rocks?
6. Based on the reference table, what are the characteristics of mafic igneous rocks?