if Boston and its Vicinity. 181 



CLASS IhS^LIJ^E FOSSILS, 



r 



Genus I. — Iron, 



SPECIES I.— SULPHATE OF IROJ^. 



r 



Sulphate of Iron, Cleaveland, p. 503. Iron Vitriol, Jameson^ vol. ii. p. Si;, 

 Green Vitriol, ^ikin, p. 262. Copperas of Artists. 



External Characters, 



Its colours are white and green. Of white, it occurs greenish 

 white ; and of green, pale asparagus green. 



Its lustre is glimmering, and vitreous, or dull. 



It is opaque. 



Its taste is acid and astrinaient. 



It has a saline 



Chymical Characters. 



1 



When exposed to heat, it becomes converted into the red 

 oxide of iron ; when dissolved in water, it gives a blackish pre- 

 cipitate or colour with tincture of galls. 



Geological Situation and Localities. 

 It occurs with a vein of Sulphuret of Iron, in Greenstone, at 



Concord ; and efflorescent on Argillite and massive Sulphuret of 

 Iron, at Charlestown. 



Remarhs, 



It is formed by the decomposition of Sulphuret of Iron, and 

 exists in small quantities only. 



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