Ores of Manganese

Pyrolusite, MnO₂, Mn . 63.2, O . 36.8.—H = 2.0-2.5, G = 4.82. Color, iron-black to steel-gray. Lustre, non-metallic. Heated in an ignition tube yields generally a little water, and if the temperature be high enough, oxygen is evolved. Before the Bp. on Ch. infusible. In borax bead gives characteristic color.

Psilomelane, Mn₂O₃ + H₂O.—

H = 5.5-6.0, G = 3.7-4.7.

Color, iron-black to steel-gray. Generally resembles pyrolusite, but is distinguished from it by its superior hardness. It frequently contains BaO and Li₂O. It behaves before the Bp. like pyrolusite.

Wad (Bog Manganese).—This mineral is essentially MnO₂, MnO, and H₂O, with small quantities of Fe₂O₃, Al₂O₃, BaO, SiO₂, etc., associated with it.

H = 0.5-6.0, G = 3.0-4.2. Color, dull black. Heated in an ignition tube yields water in abundance, otherwise it behaves like pyrolusite.