Mineral Classification—What's in a Name?

Dave Mogk and Dexter Perkins
,
Montana State University, Bozeman and University of North Dakota


Summary

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.

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Context

Audience

This activity is designed for an undergraduate required course in mineralogy and is generally for sophomore or junior level students.

Skills and concepts that students must have mastered

Students should have knowledge of basic chemistry and of minerals equivalent to what they would learn in an introductory geology class.

How the activity is situated in the course

This activity is a stand-alone exercise, but is part of a larger volume of classroom and laboratory activities from "Teaching Mineralogy," a workbook published by the Mineralogical Society of America, Brady, J., Mogk, D. W., and Perkins, D., (editors), 1997,406 pp. This activity is the 4th of 36 mineralogy exercises and is used at the beginning of the course after reviewing mineral identification based on physical properties and before systematically looking at groups of minerals.

Goals

Content/concepts goals for this activity

  • Become familiar with the most important mineral properties used for mineral identification.
  • Become familiar with some historical aspects of mineral science.

Higher order thinking skills goals for this activity

  • Practice analyzing a complex problem, synthesizing information of different sorts, and deriving a logical and practical mineral classification scheme.
  • Evaluate ways early mineralogists approached mineral classification.
  • Develop observational, descriptive, analytical, and interpretive skills.
  • Exercise hypothesis testing and critical thinking skills.

Other skills goals for this activity

  • Exercise collaborative/cooperative learning and get comfortable working in small groups.
  • Practice peer critiquing and evaluation.

Description of the activity/assignment

Students think about the nature of classification systems and about properties that are most useful for classifying minerals as they derive their own hierarchical scheme, or key, for identifying and naming mineral species. When finished, they read Mineralogy: A Historical Review by Robert M. Hazen and revise their classification scheme. Finally, groups trade their systematic plans and identify unknown mineral samples with them, comenting on the usefullness of the various methods.

Determining whether students have met the goals

There is no right answer, but students must be able to justify their reasons for selecting the order of criteria in their classification systems.

Students prepare critiques of their own and of other group's classification systems and the depth and insight displayed in their critiques reveals whether the activity was a success.

More information about assessment tools and techniques.

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