Definition of "phlogopite" [phlog•o•pite]

• A yellow to dark brown mica, K(Mg,Fe)3AlSi3O10(OH)2, used in insulation. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The name phlogopite, named by F.A. Breithaupt in 1841, comes from the Greek word phologopos meaning fiery in reference to the reddish color seen on some specimens of this mica."
• "Vermiculite is formed by the alteration and/or weathering of the minerals biotite and phlogopite."
• "The breakdown of biotite and phlogopite creates vermiculite."