

MANGANESE. 189 



The name pyrolusite is from the Greek pur, fire, and luo, 

 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, 2 Mn + Mn 2 , which contains 

 72 1 per cent, of manganese, when pure. Brownish black and sub- 

 metallic, occurring massive and in square octahedrons. H. =5-5*5. 

 G. =47. From Thuringia and Alsatia. Hdcerolite 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 5. 

 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. =4 3-4 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. Essentially 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. Mn 2 H a . 



Pelngite. The manganese nodules found in many regions over the 

 bottom of the ocean. Affords, according to an analysis, about 40 per 

 cent, of Mn0 2 , 27 £e0 3) 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. 



