\ 



of Boston and its Vicinitt/, 18/ 



It is hard. 



The fracture is imperfectly small flat conchoid al ; fine grained 

 uneven passing to earthy ; some rare specimens show a diverging 

 radiated fracture, which arists from a peculiar aggregation of cu- 

 bick crystals, 

 , It is brittle. 



It is easily frangible. 



The fragments are angular and not particularly sharp edged. 



The specifick gravity is from 4.00 to 5.00. 



Chymical Characters. 



J 



Before the hlowpipe it splits and becomes reddish ; yielding 

 a bluish flame, and a strong sulphureous odour; it fuses into a 



r 



porous black slag. AVhen projected in powder into burning coalsp 

 it yields the odour and flame of burning sulphur. 



Geological Situation and Localities. 



It occurs disseminated in Argillite, Novaculite, and Green- 

 stone, at Charlestown, Brighton, Concord, Dedham, Milton, &c. 

 &c. and in rolled masses of Granite, at Reading and Stoneham ; 

 and in Sulphuret of Copper, at Woburn ; massive in Clay, at 

 Charlestown. 



Me marks. 



It is decomposed by atmospherick exposure, and converted in- 

 to Sulphate of Iron- The massive variety is very rare. 



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