Skarns are a type of rock that develops in the vicinity of igneous intrusions when sizable amounts of aluminum, silicon, iron, and magnesium are introduced to limestone or other sedimentary rocks chiefly composed of carbonates. Skarns may contain a wide variety of minerals, including those of economically important ores, such as copper.

Cordierite is a blue magnesium aluminosilicate mineral that is sometimes utilized as a gemstone. Indeed, samples that have been procured from Sri Lanka are sometimes referred to as water sapphires. A synthetic variety of the mineral, however, which has a very low coefficient of thermal expansion and excellent resistance to thermal shock, is primarily used in items such as electrical insulators and high performance resistors. Among the other notable characteristics of cordierite is its pronounced pleochroism, or propensity to exhibit different colors when viewed along different axes. In fact, this aspect of cordierite is the origin of its alternate name, dichroite.

Among the minerals that are often associated with cordierite is anthophyllite, a member of the amphibole group. Commonly found in metamorphic and metasomatic rocks, anthophyllite derives its name from the Latin word for “clove,” a reference to its characteristic clove-brown coloration. The mineral occurs in both prismatic and fibrous crystalline forms, the latter of which is sometimes utilized as asbestos. Some of the most notable deposits of anthophyllite are located in Montana, Pennsylvania, Canada, Greenland, and Italy.

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 01:19 PM

Access Count Since November 20, 2003: 16246

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