External Symmetry of Crystals, 32 Crystal Classes
http://www.tulane.edu/~sanelson/eens211/32crystalclass.htm

Stephen Nelson, Tulane University


This site is a lecture by Dr. Stephen Nelson from Tulane University that explores the 32 possible combinations of symmetry operations that define the external symmetry of crystals. The lecture defines the six crystal systems (triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and isometric) and explains the derivation of the Hermann-Mauguin symbols (also called the international symbols) used to describe the crystal classes from the symmetry content. Tables and illustrations accompany the text.

This description of a site outside SERC has not been vetted by SERC staff and may be incomplete or incorrect. If you have information we can use to flesh out or correct this record let us know.


Part of the Cutting Edge collection. The NAGT/DLESE On the Cutting Edge project helps geoscience faculty stay up-to-date with both geoscience research and teaching methods.

Cutting Edge

Subject: Geoscience:Geology:Mineralogy:Crystallography, Geoscience:Geology:Geochemistry
Resource Type: Course Information:Course Site:Course Notes, Audio/Visual:Images/Illustrations
Grade Level: College Upper (15-16)
Course Type: Upper Level:Mineralogy
Topics: Chemistry/Physics/Mathematics, Solid Earth, :Mineralogy:Crystallography, Solid Earth:Geochemistry