ContextAudience: mid-level mineralogy course.
Setting: This assigment could be used towards the end of the semester, perhaps as a final homework assignment or a self-paced review exercise that the students could work through to prepare for a final exam. Alteratively, the exercise could be split up and assigned over the course of the semester as weekly extra-credit assignments or quizzes.
How the activity is situated in the course:This exercise covers a wide variety of mineral structures, building on concepts such as crystal system, coordination number, valence state, crystal chemistry, polymorphism, silica polymerization and silicate mineral classes, as well as non-silicate minerals. It would probably be best to use this activity as a review exercise towards the end of a course, perhaps as a study aid for a final exam.
GoalsContent/concepts goals for this activity: Students who complete this exercise should be able to use a crystallographic visualization program such as CrystalMaker or XtalDraw to determine properties of mineral structures, including:
- coordination polyhedra
- element occupancies in various crystallographic sites
- symmetry operations within crystal structures.
Higher order thinking skills goals for this activity: This exercise requires students to apply the abstract concepts of symmetry and coordination to actual crystal structures. Spatial thinking skills are also used to visualize the three-dimensionality of the crystal models with the computer (3-D glasses can be used with CrystalMaker to facilitate spatial learning).
Outcomes and EvaluationThe exercise is formatted as a self-paced exercise where students can check their own answers by clicking on "Show answer" tabs. The exercise could be reformatted as a normal homework assignment without the answers given. If used as an evaluative instrument, outcomes could be any of the following:
- written short answers to the questions
- longer integrative writing assignments
- verbal articulation of answers to peers or instructors
Longer-term uses of this exercise might be achieved if you refer to this exercise throughout the course in order to make connections between different content areas, for example, when you...
- talk about the determinative properties of minerals
- introduce new mineral groups in hand sample
- introduce the techniques of x-ray diffraction
- explain why different minerals give different powder (or precession) patterns
These questions could easily be ammended to meet your own instructional needs, or use these questions as models for developing similar exercises for other crystal structures.