Microscopy Primer
Light and Color
Microscope Basics
Special Techniques
Digital Imaging
Confocal Microscopy
Live-Cell Imaging
Photomicrography
Microscopy Museum
Virtual Microscopy
Fluorescence
Web Resources
License Info
Image Use
Custom Photos
Partners
Site Info
Contact Us
Publications
Home

The Galleries:

Photo Gallery
Silicon Zoo
Pharmaceuticals
Chip Shots
Phytochemicals
DNA Gallery
Microscapes
Vitamins
Amino Acids
Birthstones
Religion Collection
Pesticides
BeerShots
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery

Polarized Light Microscopy Digital Image Gallery

Augen Gneiss

A medium- to coarse-grained rock, gneiss is primarily distinguished by its characteristic banding caused by the segregation of its mineral constituents. Unlike schist, however, gneiss does not readily cleave along these parallel layers.

View a second image of Augen Gneiss

Gneiss is difficult to describe because it varies to such a wide extent. Nevertheless, generally the rock contains relatively large amounts of feldspar and quartz, as well as mica or some other dark, rock-forming mineral. The bands of the rock, which is formed via high-grade regional metamorphism, may be nearly parallel to the ground or steeply angled. The precise orientation of the bands may be in some way determined by characteristics of the parent rock or the type of stresses undergone during metamorphism.

Gneisses are classified based upon a variety of characteristics, such as constituent minerals, parent materials, and chemical composition. Some, such as augen gneiss, are also described based upon their structure. This type of gneiss gains its name from the elliptic or lens-shaped form of many of its mineral grains. Indeed, the word augen is German for “eye,” a reference to the appearance of these readily visible components of metamorphic rocks. To some people, an augen structure appears more akin to nuts than eyes. In fact, the scenic Hickory Nut Gorge in North Carolina is believed to have been named for the nut-shaped minerals found in much of the exposed rock present in that location.


BACK TO THE ROCKS AND MINERALS GALLERY

BACK TO THE POLARIZED LIGHT GALLERY

Questions or comments? Send us an email.
© 1998-2013 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Tuesday, Jul 25, 2006 at 10:33 AM
Access Count Since November 20, 2003: 11233
For more information on microscope manufacturers,
use the buttons below to navigate to their websites: