126 MINERALOGY AND LITHOLOGY. 



found there, and he thinks that the prehnite which occurs there had deceived the 

 finder. 



84. AuTUNiTE [Ca U' P2 O^^ + loH^ O]. 



This rare mineral has been foinid in little scales in the mica quarries 

 at Acworth. The scales are little tabular crystals of the orthorhombic 

 system. Its colors are light green and straw yellow. They are planted 

 on the feldspar. 



85. Wolframite [(Fe, Mn) W O^]. 



This heavy black mineral, which is everywhere a common associate of 

 tin ores, has been identified as occurring in small amounts in the veins 

 at Jackson with the cassiterite. 



86. Barite [Ba S O^]. 



This mineral has been found at Piermont. It occurs in bunches, and 

 nests in the specular iron ore on Cross hill. It is white. There is little 

 probability that it can be found in any such quantity as to make it an 

 economic mineral. 



87. Melanterite (Green Vitriol) [Fe 8 0' + 'jW O]. 



In several parts of the state this salt is found as a result of the alter- 

 ation and oxidation of iron pyrites. It occurs as a pulverulent kind of 

 efflorescence, with a sweetish, astringent taste, and of a greenish-white 

 color. It is soluble in water, and hence, when it forms upon the surface, 

 it is quickly removed; but in enclosed spaces under ground it is pre- 

 served in larger masses. It is noticeable as occurring in the beds of iron 

 ore at Brentwood, Gilmanton, Rindge, Hopkinton, and Plymouth. It is 

 liable, also, to be found in insignificant amounts in general in the pyr- 

 itiferous rocks where the pyrites is exposed to air and moisture. 



This salt is easily recognized by its taste. By exposure, it is further 

 oxidized to the sulphate of the sesquioxide of iron. 



88. Kalinite (Alum) [K^ AP S^ O^" + 24FP O]. 



This mineral occurs as an efflorescence upon schists and shales, and 

 is made by the action of sulphuric acid upon decomposing feldspar. It 



