GO 324 Rocks and Minerals
ES 567A Hand Specimen Petrology
Dr. Susan Ward Aber


Emporia State University
Emporia, Kansas USA
Earth Science Department

Introduction to Minerals

Crystal Systems   Formation    Names and Classification
Properties   Kansas Minerals at CSMS Geology Post References

Crystal Systems

Minerals are naturally occurring, macroscopically homogeneous, solid substances, with a definite chemical composition and characteristic atomic structure. All 4,000 plus known minerals can be divided into one of six crystal systems. These systems use three or four imaginary lines, called axes, to define the system and these axes parallel the intersection edges of major crystal faces to define the systems.

Isometric or Cubic Three equal axes; all at right angles
Tetragonal Two equal axes, one axis longer or shorter than other two; all at right angles
Orthorhombic Three unequal axes; all at right angles
Triclinic Three unequal axes; not right angles
Monoclinic Three unequal axes; two at right angles, one not
Hexagonal Three equal horizontal axes (120 degrees), one longer or shorter vertical axis

Below are three ways to visualize the crystal systems.

This image was taken from http://www4.nau.edu/meteorite/meteorite/book-glossaryc.html,
Glossary Cc by James Wittke (2009), Northern Arizona University,
Meteorite page, College of Engineering, Forestry & Natural Sciences.

This image was taken from http://www.mineralogicalassociation.ca/young/recognize.php
The Fascinating World of Minerals (http://www.mineralogicalassociation.ca/devYoung/index.php),
Mineralogical Society of Canada (http://www.mineralogicalassociation.ca/).

This image was taken from http://www.metempyrion.org/sacred_geometry.html (2008),
Metempyrion Foundation, Biophysics and Geometry,

For a more visualizations and explanations, visit

Kansas Minerals at CSMS Geology Posts

A blog well worth visiting is written by a former FHSU geology professor, Truman State University administrator, Mike Nelson. He writes informative postings on Kansas Minerals among other interesting topics. Search the blog yourself, but Of most interest as you look for specimens to add to your course specimen collections may be...

To the beginning!

Recommended References and Links

To the beginning!

Petrology Introduction
Sedimentary Rock
Metamorphic Rock
Course Field Trip
Course Syllabus
Class and Field Trip Specimen Collection

Locations of Site Visitors

This page originates from the Earth Science department for the use and benefit of students enrolled at Emporia State University. The curriculum is © by the author, 2001-2014. Creation and last update January 28, 2014. For more information contact S. W. Aber, e-mail: esu.abersusie@gmail.com or Dr. Alivia Allison, www.copyright.gov/. All rights reserved. Susan Ward Aber.