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

Alkalic Granite

The word granite derives from the Latin granum, which means “a grain,” a reference to the grained structure of the visibly crystalline rock. A popular building material for thousands of years, granite is believed to be the most prevalent plutonic rock in the Earth’s crust.

Granites form when magmas slowly cool deep within the Earth at great pressures. This process sometimes results in tabular bodies, such as sills and dikes, but the rock more often occurs in irregularly shaped masses of various sizes. Indeed, some granite masses may be extensive, reaching thousands of square kilometers in area and comprising significant parts of mountain ranges, while others are significantly smaller. The color of granite is also variable, depending greatly upon the rock’s constituent minerals and the ratios in which they occur.

Though primarily composed of quartz and feldspars, granite also frequently contains small amounts of hornblende, micas, and other minerals. Moreover, the proportion of plagioclase to alkali feldspar may differ in granite samples, which is often utilized as the starting point for granite classifications. Alkalic, or alkali, granites, for instance, are those in which the alkali feldspar content significantly exceeds the plagioclase. These types of rocks characteristically contain pyroxenes and sodic-amphiboles. In the United States, samples of alkalic granite can be found in New England, but they also occur notably in Norway and Nigeria.


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 09:33 AM
Access Count Since November 20, 2003: 10881
For more information on microscope manufacturers,
use the buttons below to navigate to their websites: