Describe rock and mineral specimens based on close observation.
- rocks* brought in by the students
- art supplies
- small hammer or scraper
- magnifying glass
- index cards
- pencils and paper
- copies of the Activity Page
*No doubt some students will select objects that are neither rocks nor minerals (e.g., wood or man-made products like plastic). This is fine, because discovering that they are not minerals is as much a part of the learning process.
1. Ask students to search their yards, play areas, or rock collections for one small specimen that they can bring into school. They can choose any object-as long as it's easy to carry.
2. Have students brush any dirt from their specimen and look at it closely. They can also wash it and look at it with a magnifying glass. Remember that if the object appears to be one substance, it is probably a mineral; if it is a composite, it is probably a rock made up of several minerals. Encourage students to observe carefully and form logical hypotheses, rather than try to identify all of the specimens. Ask them to write down the answers to the following questions about their specimens:
- Where was it found and by whom?
Knowing a rock or mineral's natural setting can help identify it.
- What color is it?
Color can be a clue to minerals. Iron, for instance, may give rocks a reddish hue.
- Is it smooth or rough?
If smooth, it's more likely to have been rounded by the action of water over long periods of time.
- Is it dull or shiny?
A shiny surface may indicate the presence of mica or quartz crystals.
- Does it scratch glass?
If so, it is probably made largely of quartz.
- Does wetting it change the color or consistency of the object?
The color may change, or what was thought to be rock may prove to be dirt or clay.
- Any additional observations? Have students compare and contrast their specimens.
3. Ask students to do the activity as either a take-home or an in-class assignment.
4. Create a classroom exhibit. Encourage students to think of their individual specimens as part of a larger collection. Have the class brainstorm ways to organize the collection into an exhibit (based on size, location found, color, etc.), number each specimen, and give the exhibition a title (for example: Rocks and Minerals of the Forest Avenue School District). Then have each student build a specimen box for his or her rock or mineral by decorating a shoebox and writing a label for their specimen, demonstrating what they have observed. Following is one example of an exhibit label, although you can add more information based on class work and after-school research. Arrange the labeled boxes on desks or tabletops. Invite other classes to visit the exhibit; students can stand by their specimens and tell visitors about them.
Sample Exhibit Label
If this activity stimulates interest in mineral identification, you can try using a prefabricated science kit or rock collection (see Resources section) and compare the class's specimens to those already labeled and identified. You can also invite a guest speaker (a local museum curator, university professor, or rock and mineral enthusiast) to visit the classroom and answer questions. The expert may help the students identify or learn more about their specimens.