n. A light brown mineral that is a source of many rare earth elements
The Century Dictionary and Cyclopedia
n. A fluocarbonate of cerium, lanthanum, and didymium from the Bastnäs mine, Sweden. It also occurs as an alteration product of tysonite near Pike's Peak, Colorado.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a yellow-to-brown mineral that is a source of rare earth elements