4.1 Overview: Petrographic Microscopes

4.1 Overview: Petrographic Microscopes

Introduction

A petrographic microscope is a type of optical microscope that uses polarized light to identify rocks and minerals in thin section and to investigate microscopic textures and features that are present in minerals and rocks.

This module provides an overview of the parts of a petrographic microscope, including the purpose of each part.  It also provides some troubleshooting advice for common issues that students encounter while using a petrographic microscope.

This module does NOT cover how to use the microscope, or the scientific principles used to identify rocks and minerals.  The content and skills necessary to master the use of the petrographic microscope are typically covered in mineralogy, igneous and metamorphic petrology, and sedimentary petrology courses.  Many textbooks have been written on optical mineralogy as well as the use of optical mineralogy in petrology courses.  Some online and textbook resources are compiled below in the References section if you would like to learn more.

https://www.virtualmicroscope.org/rock_sample?asset=smg117/index.html?x=14.41&y=9.1&zoom=0&s=0&rot=2&deg=0

Figure 4.1.1 Dunite peridotite from the Isle of Skye, Scotland, in plane polarized and cross polarized light in thin section. By The Open University (ret. 12/1/2018) Virtual Microscope. https://www.virtualmicroscope.org/ (Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence) https://www.virtualmicroscope.org/content/dunite-peridotite-%E2%80%93-isle-skye

Learning Objectives

At the end of this module, students should be able to:

Identify and describe the purpose of each part of a petrographic microscope.

Create and test hypotheses for the causes of problems experienced while using a petrographic microscope.

Prior Knowledge and Skills

None

References

Jing Niu (10/21/2012) Introduction to Optical Mineralogy. https://youtu.be/_ooSuUHGiiw

Mogk, David W. (ret. 12/1/2018) Optical Mineralogy and Petrology. https://serc.carleton.edu/NAGTWorkshops/mineralogy/optical_mineralogy_petrography.html

Nesse, W. (2012) Introduction to Optical Mineralogy, 4th edition. Oxford University Press, 384 p.

Perkins, D. and Henke, K.R. (2003) Minerals in Thin Section, 2nd edition. Pearson, 176 p. ISBN-13: 978-0131420151

Raith, M.M., Raase, P., and Reinhardt, Jurgen. (2011) Guide to Thin Section Microscopy.  ISBN 978-3-00-033606-5 https://d32ogoqmya1dw8.cloudfront.net/files/NAGTWorkshops/mineralogy/thin_section_microscopy.pdf

The Open University (ret. 12/1/2018) Virtual Microscope. https://www.virtualmicroscope.org/

Tramontino, S. (2015) Earth Optics Mineralogy Optical Mineralogy. https://earthopticsmineralogy.com/

Waters, D.J. (06/2004) Rocks under the Microscope. https://www.earth.ox.ac.uk/~oesis/micro/

License and Attributions

Text written by Elizabeth Johnson, James Madison University (JMU)

CC-by License