Teaching Notes


Audience: mid-level mineralogy course.

Skills and concepts that students must have mastered: This activity assumes students are familiar with the olivine crystal structure and are familiar with the concept of order/disorder within crystals. Students should also know how to use Excel to make x-y graphs.

How the activity is situated in the course: This activity could supplement class lectures on order/disorder, solid solutions, or nesosilicate mineral structures.


Content/concepts goals for this activity: Students who complete this exercise should be able to:
  1. Use the American Mineralogist Crystal Structure Database to obtain crystal structures of synthetic olivines.
  2. Use a crystallographic visualization program (such as CrystalMaker or XtalDraw) to identify which elements are housed in which crystallographic sites in the olivine structure.
  3. Use downloaded olivine compositions and Excel to determine the ordering of M1 and M2 cations within olivine.

Higher order thinking skills goals for this activity: This exercise requires students to apply the abstract concept of crystallographic order to a dataset in which the amount of order within two cation sites is temperature-dependent. Students are also asked to think about the relationship between crystallographic order and entropy.

Other skills/goals for this activity: Students gain practice in (1) using crystallographic software to solve geologic problems, (2) using an Excel program to plot data, and (3) writing answers to open-ended questions.

Outcomes and Evaluation

This activity 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.