pyrosmalite

from The Century Dictionary.

• noun A mineral of a liver-brown color, or pistachio-green, occurring in six-sided prisms, with perfect basal cleavage, found in Sweden. It is a silicate of iron and manganese, containing chlorin, the odor of which it exhales when heated.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A mineral, usually of a pale brown or of a gray or grayish green color, consisting chiefly of the hydrous silicate of iron and manganese; -- so called from the odor given off before the blowpipe.

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

• noun mineralogy A mineral, usually of a pale brown or grey-greenish colour, consisting chiefly of the hydrous silicate of iron and manganese.