Beacon Lesson Plan Library

What Is in a Rock?

Terrie Lyons
Santa Rosa District Schools


Students identify, sort, and classify mineral samples that make up a common rock.


The student knows the relationship between run-off and the development of the river system.


-Samples of granite rock, finely crushed (one film canister full is enough for a whole class)
-At least ten samples each of the following minerals: quartz, mica, feldspar
-1 hand lens for each student
-2 toothpicks for each student
-A copy of the Venn diagram worksheet for each student (See Associated File)
-Rock and mineral identification guides or textbooks


1. Download and run off the Venn diagram worksheet (See Associated File), or create your own classification worksheet. Each student needs one.
2. Crush samples of granite into small grains. A hammer is useful for this. You do not need a lot of sample. A film canister full is enough for an average size class.
3. Obtain enough hand lenses and toothpicks for each member of the class to have their own equipment.
4. Obtain at least 10 samples each of quartz, mica, and feldspar.
5. Obtain mineral identification guides or textbooks.


PRIOR KNOWLEDGE: Students should be familiar with the following terms and/or characteristics: mineral, luster, cleavage, and crystal shape.

1. Ask the class as a whole, what makes up a rock? Allow for student response. Students should come to the answer that a rock is made up of two or more minerals. Have the students state the definition of a mineral.

2. Tell the students, “Today we are going to investigate the minerals that make up the common rock granite. We will be classifying them according to color, shape, and luster.”

3. Give each student a copy of the Venn diagram. (See Associated File)

4. On the cross-marked area of the Venn diagram, place a small sample of the crushed granite.

5. Provide each student with a hand lens and two toothpicks. Have mineral identification guides and textbooks available for student reference.

6. Instruct the students to use the lens and toothpicks to sort the grains of ground rock sample according to color, luster, and shape. Using the toothpicks, students place the grains in the appropriate areas of the diagram. At this point all of the piles should contain similar-looking material.

7. Students now use the hand lens to observe and describe each pile using such words as cleavage, luster, color, and crystal shape. Instruct them to write these observations on their diagram in the appropriate place.

8. Provide each student with a large sample of one of the following minerals: quartz, feldspar, or mica. Have them compare their sample to the small grain samples and place the large sample with the appropriate grouping on the diagram.

9. Have the students compare their classifications with the pictures of the different minerals found in the identification guide or their textbook. At this point, a class discussion of the exercise and classifications would be appropriate. Have students share with the class their answers to the worksheet questions. This will provide a good wrap-up and review of the material covered.
(Note: Student responses to worksheet questions will vary.)

10. At the end of the activity, collect all samples and materials used.


As a formative assessment, observe students as they sort and classify their granite sample into the proper mineral categories. Students can also be assessed on the proper use of the lab materials given them, such as the hand lenses, toothpicks, and mineral samples.


The procedure could be modified to allow it to be used as a cooperative group activity for ESE/ESOL students or if there are not enough supplies for each student to have their own individual set.

Attached Files

The attached file contains the Venn diagram worksheet.     File Extension: pdf

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