Tags: Chemical Substance, Mineral.
Wiluite is a dark green brownish or black blocky silicate mineral with formula: Ca19(AlMgFeTi)13(BAl[ ])5Si18O68(OOH)10. It has a Mohs hardness of 6 and a specific gravity of 3.36. It has a vitreous lustre poor cleavage and an irregular brittle fracture. It crystallizes in the tetragonal system and occurs as well-formed crystals with good external form.
