MANGANESE. 189 
The name pyrolusite is from the Greek pwr, fire, and lwo, 
to wash, and alludes to its property of discharging the 
brown and green tints of glass, for which it is extensively 
used. . 
Besides the use just alluded to, this ore is extensively em- 
ployed for bleaching, and for affording the gas oxygen to 
the chemist. 
Hausmannite. A manganese oxide, 2Mn0O+ Mn O,, which contains 
72:1 per cent. of manganese, when pure. Brownish black and sup- 
metallic, occurring massive and in square octahedrons. H.=0-0°6. 
G.—4:'7. From Thuringia and Alsatia. Hetwrolite is a zinc-hausman- 
nite, from Sterling Hill, N. J. 
Braunite. An oxide of manganese, containing 69 per cent. of man- 
ganese when pure. Color and streak dark brownish-black, and lustre 
submetallic. Occurs in square octahedrons and massive. H.=6-6°9. 
G.=4°8. From Piedmont and Thuringia. 
Manganite. A hydrous sesquioxide of manganese. Occurs massive 
and in rhombic prisms. Color steel-black to iron-black. H.=4-4°5. 
G.=43-4:4. From the Hartz, Bohemia, Saxony, and Aberdeenshire. 
It is found at several points in New Brunswick and Nova Scotia. 
Psilomelane. 
Massive and botryoidal. Color black or greenish-black. 
Streak reddish or brownish-black, shining. H.=5-6. G.= 
4—4°4, 
Composition. Kssentially manganese dioxide with a little 
water, and also some baryta or potassa. The compound is 
somewhat varying in its constitution. Before the blowpipe 
like pyrolusite, except that it affords water. 
Obs. This is an abundant ore, and is associated usually 
with the pyrolusite. It occurs at the different localities 
mentioned under pyrolusite, and the two are often in alter- 
nating layers; it has been considered an impure variety of 
the pyrolusite. ‘The name is from the Greek psilos, smooth 
or naked, and melas, black. ; 
Pyrochroite. Hydrous manganese protoxide, of white color. From 
Sweden. MnO, H.,. 
Pelugite. The manganese nodules found in many regions over the 
bottom of the oczan. Affords, according to an analysis, about 40 per 
cent. of Mn O0,, 27 HeO,, 13 of water lost at a red heat, along with 14 
per cent. of silica and 4 of alumina; 24:5 per cent. of water were 
lost below 100° C. Probably a mixture. 
Chalcophanite. A hydrous oxide of manganese and zinc, in rhombo- 
hedral crystals and stalactites ; from Sterling Hill, N. J. 
