ORES OF MANGANESE. 53 



ORES OF MANGANESE. 



The most valuable of these ores are the oxides, of which there are several distinct species 

 and varieties. The mineral most abundant in this State, is that which is known by tlic name 

 of the Earthy Oxide of Manganese, or Wad. 



Descuiption. The colour of tliis mineral is brownish, or iron-black ; it has an earthy ap- 

 pearance, and it is usually mixed with other substances, as silica, alumina, oxide of iron, 

 carbonate of lime, and vegetable matter. It is often friable, easily reducible to powder, and 

 strongly soils the fingers ; sometimes, however, it has a fibrous texture, the fibres radiating 

 from a common centre. 



It is infusible by the blowpipe, but is converted by it into brownish oxide. It communicates 

 a violet colour to borax. Heated with sulphuric acid, it gives out oxygen gas ; but with mu- 

 riatic acid, it exhales the odour of chlorine. 



From recent researches, it appears that the variety known by the name of wad, differs in 

 containing a portion of water, and it has the chemical name of hydrated peroxide of manga- 

 nese, although all the varieties of this oxide are indiscriminately applied to the same uses in 

 the arts. These are in the preparation of chlorine for bleaching, and in the manufacture of 

 glass. It is not improbable that it may be found in this State in considerable quantities, of a 

 sufficient degree of purity for all these purposes. 



Columbia County. According to Mr. Mather, wad is found in some abundance in a nar- 

 row range in this county. " It is deposited," says he, " from solution in water, in marshes, 

 like bog iron ore. It has been found in quantity only in the vicinity of a range of slate, in- 

 jected with quartz veins, which contain brown spar. Wlicn this spar is decomposed, oxide of 

 manganese remains, which frequently retains the crystalline texture of the spar. This quartz, 

 when exposed to the air, soon loses the brown spar by decomposition, and becomes cellular in 

 consequence. The manganese of the wad is supposed to be derived from the brown spar 

 which has been decomposed, and the constituents of which have been transported by water 

 into the low grounds where the manganese is deposited. Brown spar is composed of the 

 carbonates of lime, magnesia, iron and manganese ; and as these bodies are isomorphous, 

 they may replace each other without changing the crystalline form. The brown spar of this 

 range of rock seems to contain an unusually large proportion of manganese."* 



Such is the explanation given by Mr. Mather of the occurrence and mode of formation of 

 this mineral, to which I have nothing to add at present. Several localities have been noticed 

 in this county, among which are the following, viz : , 



* New-York Geological Reports, l%38. 



