|
|
Article: Epitaxy.(Word to the Wise)
- Article from:
- Rocks & Minerals
- Article date:
- July 1, 2006
- Author:
CopyrightCOPYRIGHT 2006 Heldref Publications. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
Many mineral specimens--and by definition almost all rocks--are intergrowths of crystals. Crystals in an intergrowth are usually randomly oriented, but those exceptions, where we find nonrandom or crystal-lographically controlled intergrowths, are fascinating and often quite beautiful in their symmetry. One of several types of nonrandom (or regular) crystal intergrowths is epitaxy.
Generally speaking, epitaxy is the oriented overgrowth of one mineral or crystalline material on another. In this case, specific crystallographic directions of the substrate and overgrowth are aligned. This occurs when certain structural planes in the overgrowth and the substrate have ...