Teach the Earth > Petrology > Teaching Activities > Introduction to Mineral Equilibria

Introduction to Mineral Equilibria

Dexter Perkins
University of North Dakota
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This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.

This page first made public: Jan 17, 2006


This activity features a short problem set to be used in class. It helps focus the discussion, while providing a starting point for an introduction to mineral reactions and phase diagrams.

Used this activity? Share your experiences and modifications



I use this project in an undergraduate Petrology class. The class is taught in a studio format. The students form groups to do projects and work on problem sets such as this one in class. After we compare answers the solutions are used to segue into the next activity.

Skills and concepts that students must have mastered

Before the students attempt this activity, instructors should discuss the phase rule, explain what P, C and F are, detail how many degrees of freedom correspond to a reaction, describe an invariant point, etc. Students will also need some explanation about how to plot compositions on a ternary diagram.

How the activity is situated in the course

This is an introductory problem set to get students thinking about mineral equilibria. It precedes most lecturing on the subject.


Content/concepts goals for this activity

After completing this exercise, students should be able to:
-Plot mineral compositions on a ternary diagram.
-Apply the phase rule to determine how many minerals may coexist under what conditions.
-Use a phase diagram to determine the conditions where a particular minerals assemblage is stable.

Higher order thinking skills goals for this activity

The project involves visualization and extrapolation.

Other skills goals for this activity

Group work.

Description of the activity/assignment

This is short problem set to be used in class. It helps focus discussion, while providing a starting point for discussing mineral reactions and phase diagrams. Students are exposed to ternary composition diagrams and to phase diagrams. They are also introduced to the phase rule, although in quite a superficial way.

Determining whether students have met the goals

Simple-if they complete it, they have met the goals. They do not have to get the correct answers because that is what the plenary wrap-up is about.

More information about assessment tools and techniques.

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