A zincian manganoan variety of augite, a clinopyroxene.
Originally described from Passaic Pit (Marshall Mine; Passaic Mine), Sterling Hill, Ogdensburg, Franklin Mining District, Sussex Co., New Jersey, USA.
(TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.