cobaltite

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A rare silver-white to gray mineral, cobalt sulfarsenide, CoAsS, that is a cobalt ore and is used in ceramics.

from The Century Dictionary.

• noun A sulpharsenide of cobalt. It is a mineral of a silver-white color, with a tinge of red, occurring in isometric crystals, often cubes or pyritohedrons. Also called cobalt-glance.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy A rare, gray mineral, a mixed sulfide and arsenide of cobalt and iron with the chemical formula CoAsS; it is an ore of cobalt.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a rare silvery-white mineral; important ore of cobalt