Nepheline, which is the most common of a group of minerals called feldspathoids, is a primary component of several igneous rocks, including ijolite. Presence of nepheline is often an indication that the rock in which it is contained is alkali-rich.

The crystalline rock ijolite is considered the plutonic analogue to olivine-poor nephelinites and nepheline dolerites. In addition to nepheline, it is chiefly composed of an alkali pyroxene mineral, but may also contain various other materials, such as calcite, sphene, melanite, wollastonite, and pectolite. Relatively rare, it may be found in Magnet Cove, Arkansas, Iron Hill, Colorado, the Kola Peninsula of Russia, and Canada’s Ice River, among other less well-known locales. Sometimes characterized as a type of gabbro, when ijolite does occur, it often appears as a component of carbonatite–alkali igneous complexes.

Questions or comments? Send us an email.

© 1998-2022 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: Friday, Nov 13, 2015 at 02:19 PM

Access Count Since November 20, 2003: 14375

For more information on microscope manufacturers,
use the buttons below to navigate to their websites: