The Collaborative International Dictionary
Dufrenite
Dufrenite \Du*fren"ite\, n. [From ??ierre Armand Dufr['e]noy, a French geologist.] (Min.) A mineral of a blackish green color, commonly massive or in nodules. It is a hydrous phosphate of iron.
Wiktionary
dufrenite
n. (context mineral English) A blackish-green mineral that is a hydrous phosphate of iron.