piedmontite

from The Century Dictionary.

• noun A mineral closely related in form and composition to epidote, but containing manganese, hence sometimes called manganepidote. It is of a reddish-brown color, and is found at St. Marcel in Piedmont.

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

• noun (Min.) A manganesian kind of epidote, from Piedmont. See epidote.

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

• noun mineralogy A manganic variety of epidote.