Sillimanite
Description
A fibrous or prismatic aluminum silicate mineral. Sillimanite was named in honor of Benjamin Silliman, a professor of mineralogy at Yale. It was previously called fibrolite. Sillimanite is found in South Africa, India, Germany (Bavaria), France, the Czech Republic, Scotland, United States (California, New York, Pennsylvania, South Carolina, Delaware, Connecticut, Massachusetts) and southeast Asia. Its color is usually a brown or gray, but stones found in southeast Asia are a gem quality sapphire blue. Sillimanite is a refractory material with high heat resistant. It is used for kiln brick, spark plugs, and laboratory items.
Synonyms and Related Terms
fibrolite; aluminum silicate; bucholzite; Sillimanit (Deut.);
Other Properties
Orthorhombic crystal system; usually occurs as fibrous mass. Perfect cleavage in one direction.
Fracture = uneven or splintery. Luster=vitreous. Streak = colorless.
| Composition | Al2SiO5 |
|---|---|
| Mohs Hardness | 6.0 - 7.5 |
| Melting Point | 1900 |
| Density | 3.23-3.24 |
| Refractive Index | 1.65; 1.66; 1.68 |
Additional Information
Mineralogy Database: Sillimanite
Authority
- Robert Fournier, Illustrated Dictionary of Practical Pottery, Chilton Book Company, Radnor, PA, 1992
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Encyclopedia Britannica, http://www.britannica.com Comment: "Sillimanite." Encyclopædia Britannica. 18 Aug. 2004 .
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Sillimanite (Accessed Nov. 9, 2005)