The mineral group alleghanyite, chondrodite, clinohumite, humite, jerrygibbsite, leucophoenicite, manganhumite, norbergite, ribbeite, and sonolite; monoclinic and orthorhombic fluosilicates of magnesium, iron, and/or manganese, with hydroxyl commonly replacing fluorine; similar physical properties, and structures closely related to those of the olivines; in metamorphosed dolomitic limestones, or skarns associated with ore deposits; commonly as chondrodite and clinohumite; at the Tilly Foster iron mine near Brewster and at Franklin, NJ.