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DESCRIPTIONS OF MINERALS. 



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MANGANESES. 



The common ores of manganese are the oxides, the car- 

 bonate, and the silicates, There are also sulphides, an 

 arsenide, and phosphate. They have a specific gravity be- 

 low 5 -2. 



Manganese Sulphides and Arsenide, 



Aldbnndite or Manganblende. A manganese sulphide MnS, of an 

 iron-black color, green streak, submetallic lustre. H. — 3 - 5-4. G.= 

 S^-^O. Crystals, cubes and regular octahedrons. From the gold 

 mines of ^agyag, in Transylvania. 



Hauerite. A sulphide, MnS-, containing twice the proportion of 

 sulphur in the last. Color reddish brown and brownish black, re- 

 sembling blende. H. =4. Gr. — 3 # 46. From Hungary. 



Kondte is a manganese arsenide, of a grayish-white color, and 

 metallic lustre, which gives off alliaceous fumes. G.=o"o5. From 

 Saxony. 



Pyrolusite. — Manganese Dioxide. 



Trimetrie. In small rectangular prisms, more or less 

 modified. I A 1=93° 40'. Sometimes 



fibrous and radiated or divergent. Of- 

 ten massive and in reniform coatings. 



Color iron-black : streak black, non- 

 metallic. H.=2-2-5 G.=48. 



Composition. Mn 2 = Manganese 

 632, oxygen 36 '8=100. A minute 

 portion of it imparts .to a borax bead 

 a deep amethystine color while hot, 

 which becomes red-brown on cooling. It yields no water 

 in a matrass. 



Diff. Differs from psilomelane by its inferior hardness, 

 and from ores of iron by the violet glass with borax. 



Obs. This ore is extensively worked in Thuringia, Mo- 

 ravia. and Prussia. It is common in Devonshire and Somer- 

 setshire, in England, and in Aberdeenshire. In the United 

 States it is associated with the allowing species in Ver- 

 mont, at Bennington. Brandon, Monkton, Chittenden, and 

 Irasburg : it occurs also in Maine, at Conway, and Plain- 

 field in Massachusetts ; at Salisbury and Kent, in Conn., 

 on hematite : on Pied Island, in the Bay of San Francisco ; 

 at Pictou and Walton, Isova Scotia ; near Bathurst, in 

 New Brunswick. 





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