fersmanite

fersmanite

[′fərz·mə‚nīt]
(mineralogy)
(Na,Ca)2(Ti,Cb)Si(O,F)6 A brown mineral composed of a silicate fluoride of sodium, calcium, titanium, and columbium.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.