Starting Point-Teaching Entry Level Geoscience > Indoor Labs > Working with rocks, minerals and fossils
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Working with Earth Materials

Many students come into introductory geoscience classes with the assumption that ALL labs in the course will involve rocks and minerals (earth materials). Whether or not this is true for your course, you probably WILL offer at least a few labs where they work with rocks and minerals in some ways. In developing these labs, here are a few questions to consider:

Finding sources for mineral and rock specimens

Several commercial companies offer rock and mineral specimens for sale, as complete collections of small specimens, or as single specimens. We find that the smaller (and less expensive) "student specimens" (including those in the "collections") are too small to show important features (like foliation in metamorphic rocks). They are also more likely to disappear. We've found it useful to order several of the "hand specimen" size (generally 2" x 3" to 3" x 4")and then cut each one in half with a rock saw to make up sample sets for student groups of three or four to work on together. (And you can easily cut a thin-section chip at the same time). You can expect to pay more for, say, four hand specimens (to serve eight groups of three in a 24-student lab) than for student-sized specimens for each student.

If you want rock or mineral specimens with certain features (for example, clear cleavage planes in a pyroxend specimen), you'll probably want to work with the company representative to look over some trial specimens. The representative will also be a good source of information about the provenance of the rocks and minerals, information that's unlikely to be very detailed in either print or web catalogs.

In another approach, you can also develop a working rock and mineral collection for introductory geoscience by collecting materials that crop out near your area. North of the glacial margin, you are likely to find glacially transported boulders of igneous and metamorphic rocks that can easily be broken or cut into enough pieces to form a good collection. Some departments send faculty and students on summer excursions specifically to collect rocks for a department teaching collection.

A set of rocks can also be collected and prepared that will tie into a lab reconstructing the geologic history of a particular region (e.g. the Grand Canyon or the Black Hills). These "suites" help students combine rock description with analysis of topographic and geologic maps.

Many student geology clubs at colleges and universities sell rocks and minerals as fundraisers. Western Illinois University, and University of Missouri, Columbia are two examples. Rock sets may also be available through state geological surveys or geological societies, for instance, the Connecticut Geological and Natural History Survey.