Mineral Classification: What's in a Name

Dave Mogk, Montana State University.

This page is a supplement to the original activity description found here

Short description of the activity:

Students derive their own scheme for identifying and naming minerals. Examples include different minerals that have the same crystal forms, and mineral species that occur with numerous forms and varieties to demonstrate the diversity of the mineral world. This exercise introduces the ambiguities encountered in classifying minerals that lead ultimately to the development of Dana's system of mineralogy

How does this activity lend itself to teaching the methods of geoscience?

I use this activity as the first lab exercise in my Mineralogy course to introduce students to the complexity they will encounter in the mineral world. They encounter a number of challenges and practices that are common to our professional practice:

1. How to make systematic, and consistent observations;
2. Need for preciseness and clarity in communicating ideas (just what is meant when we say a mineral is "metallic"?
3. Ambiguity: multiple varieties of quartz are provided--all different, yet all the same;
4. The students' classification scheme must be simple, transportable, and usable by other groups, a very difficult challenge!
5. The classification scheme of each student group must be replicable--other groups must use the proposed system and be able to come up with the same distinctive mineral classes as the originators.
6. Students see the need for engaging the norms of professional practice--we all have to agree on what is acceptable evidence or we get nowhere as a discipline--thus the importance of Dana's classification scheme.
7. Emphasis in this exercise is on inquiry and discovery about the mineral world.
8. Students work collaboratively in groups--this is how we do science.
9. Rudimentary tools are provided to allow students to test physical properties of minerals.
10. The exercise includes a reflective component so that students must consider what worked, what didn't, what else they need to know and what they could do better (a metacognitive approach)

Specific Adaptations: How do these help the activity address the methods of geoscience?

The exercise was developed with extensive Notes for Instructors that details the philosophy, cognitive psychology, and pedagogy that underlies the design of this exercise. Feedback from colleagues reports that this exercise has been used widely in both introductory physical geology and mineralogy courses.

Assessment: How are the methods of geoscience assessed?

This exercise was designed to demonstrate methods of geoscience as described above. This exercise is not graded (i.e. evaluated). It is assessed via peer assessment as each classification scheme is used by another group to test its usability. In whole group discussion, we report on the difficulties, ambiguities, need for precise description and clarity of language, that are needed for the systematic coverage of topics in mineralogy. This unit is an "ice breaker", and having established course goals, methods, and environment (collaborative learning), we are set to go for the semester.