Cutting Edge > Courses > Mineralogy > Teaching Activities > Crystal Growth - Fast and Slow

Crystal Growth - Fast and Slow

Peter J. Heaney
,
Princeton University
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This activity was peer reviewed prior to publication in the Teaching Mineralogy Workbook.

This teaching activity was originally published in: Brady, J., Mogk, D. W., and Perkins, D., (editors), 1997, "Teaching Mineralogy," a workbook published by the Mineralogical Society of America, 406 pp. All teaching activities in this volume received two external peer reviews from mineralogy faculty focused on content and pedagogy, and a final review by the co-editors to comply with the publication standards of the Mineralogical Society of America.



This page first made public: May 9, 2008

Summary

This lab is divided into two exercises that may be completed within a single three-hour session. The first exercise requires the mixture of aqueous solutions that will precipitate large euhedral crystals over the course of 1 to 2 weeks. These experiments are intended to mimic the slow growth of macroscopic minerals in thermal and chemical equilibrium. In the second exercise, students observe rapid growth of dendritic crystals in strongly undercooled solutions in order to visualize the disequilibrium growth processes that occur in the atmosphere, at chilled margins, and in highly supersaturated solutions.

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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 basic concept of crystallography including Miller indicies and crystal habits.

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 should help students to understand how crystals grow and what factors affect their growth habit.

Higher order thinking skills goals for this activity

Students should be able to use observations from their experiments to explain how crystals form.

Other skills goals for this activity

This activity strengthens a student's ability to work in groups and to synthesize their results in a written format.

Description of the activity/assignment

This lab is divided into two exercises that may be completed within a single three-hour session. The first exercise requires the mixture of aqueous solutions that will precipitate large euhedral crystals over the course of 1 to 2 weeks. These experiments are intended to mimic the slow growth of macroscopic minerals in thermal and chemical equilibrium. In the second exercise, students observe rapid growth of dendritic crystals in strongly undercooled solutions in order to visualize the disequilibrium growth processes that occur in the atmosphere, at chilled margins, and in highly supersaturated solutions.

Determining whether students have met the goals

Students have met the goals of this activity if they successfully grow their crystals and are able to answer the supplemental questions accurately and completely.

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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.

Arend, H. and Hulliger, J., Eds. (1989) Crystal Growth in Science and Technology. Plenum Press, New York. (A collection of articles drawn from a NATO symposium. The treatment is highly quantitative, and the readability is variable.)

Bentley, W.A. and Humphreys, W.J. (1931) Snow Crystals. Dover, New York. (Dover has reproduced the original manuscript with 2,453 photographs of snow crystals for only $15.)

Holden, A. and Morrison, P. (1989) Crystals and Crystal Growing. MIT Press, Cambridge, MA.
(Simple discussions of crystallography aimed at the informed lay reader with lots of recipes for crystal growth.)

Klein, C. and Hurlbut, C.S. Jr (1993) Manual of Mineralogy, 21st edition. John Wiley and Sons, New York. (Chapter 2 contains an in-depth and well-illustrated discussion of crystal forms and their relation to the crystal classes.)

Langer, J.S. (1989) Dendrites, viscous fingers, and the theory of pattern formation. Science, 1150-1156. (An advanced review of mathematical models of dendrite formation.)

Smelik, E.A. and King, H.E., Jr. (1997) Crystal-growth studies of natural gas clathrate hydrates using a pressurized optical cell. American Mineralogist, 82, 88-98. (A recent article that describes the equilibrium growth forms for clathrate hydrates and the design for a cooling stage on a petrographic microscope.)

Zoltai, T. and Stout, J.H. (1984) Mineralogy: Principles and Concepts. Burgess Publishing Co., Minneapolis. (Chapter 7 contains the nicest discussion of crystal growth processes among the general mineralogy texts.)

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