Dufrenite :: Dufrenite (n.) A mineral of a blackish green color, commonly massive or in nodules. It is a hydrous phosphate of iron..
Renitency :: Renitency (n.) The state or quality of being renitent; resistance; reluctance.
Renitent :: Renitent (a.) Resisting pressure or the effect of it; acting against impulse by elastic force.