Miller Indices and Symmetry Content: A Demonstration Using SHAPE, a Computer Program for Drawing Crystals

Michael A. Velbel
,
Michigan State University
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Summary

The purpose of this exercise is to use SHAPE: A COMPUTER PROGRAM FOR DRAWING CRYSTALS to help you visualize the relationship between the morphology of crystals, Miller indices, axial ratios, crystal faces, open and closed forms to the symmetry content of the crystal.

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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 a general understanding of mineralogy and crystallography including topics such as morphology, Miller indicies, axial ratios, crystal faces, and crystal symmetry.

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.

Goals

Content/concepts goals for this activity

This activity is designed to strengthen students' understanding of crystallography including topics such as morphology, Miller indicies, axial ratios, crystal faces, and crystal symmetry.

Higher order thinking skills goals for this activity

This activity involves the development of computer models.

Other skills goals for this activity

Description of the activity/assignment

The purpose of this exercise is to use SHAPE: A COMPUTER PROGRAM FOR DRAWING CRYSTALS to help you visualize the relationship between the morphology of crystals, Miller indices, axial ratios, crystal faces, open and closed forms to the symmetry content of the crystal.
Instructions on how to create and modify crystal drawings, and how to customize the display, are included at the end of this exercise; that part of the handout is referred to as the "general instruction" handout. Use it as a reference for the specifics of how to use SHAPE for this lab. These instructions are written for older (MS-DOS) versions of SHAPE. The menu structure in Windows versions is similar. If you can't figure out how to enter some command, ask the instructor for help.
In this exercise, you will generate various crystal drawings, copy them from the screen (using colored pencils), and answer questions about intercepts, Miller indices, symmetry, etc., illustrated by each example.

Determining whether students have met the goals

Students have met the goals of this activity if they answer the questions embedded in the activity are answered thoroughly and accurately (see download).

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs

Brady, J., Mogk, D. W., and Perkins, D., (editors), 1997, Teaching Mineralogy, a workbook published by the Mineralogical Society of America, 406 pp.

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