3.2 x 0.6 x 0.6 cm (largest). Psilomelane is an obsolete group name for hard black manganese oxides. It is known to have occurred in many of the mines in the historic Bisbee District, but is very rare as preserved specimens. This excellent and very rare, two-piece set consists of nubby, very light weight, purple-gray psilomelane stalactites. Both ends of the smaller piece appear to be broken, but the larger piece has a fabulous branching and connected termination. Probably old material, but no proof. Ex. Dennis Mullane Bisbee Collection.