I 



(jf Boston and its Vicinitjj. 



163 



SPECIES X.--FIlEIimTE. 



i 



Massive or Fibrous Prelinite, Cleaveland, p. n05. Prehuite, Javwson, voT. 

 I. p. 204. Massive Prehnite, Aikin, p. 232. 



External Characters. 



Its colours are white and g 



Of white, it occurs gveen 



ish white 



and of green, leek g 



'; 



blackish green, hi 



green, asparagus green and olive green. 



Its lustre is glimmering and glistening ; and is pearly. 



It is translucent at the edsreg. 



It is amorphous, tuberous and cellular. 



The streak is greenish white. 



It is hard. 



The fracture is fine splintery, fine grained .uneven, and fine 

 diverging radiated. 



It is brittle. 



It is easily frangible. 



The specifick gravity is from about S.346 to 2.41 i. 



Chymical Characters, 



m 



Before the blowpipe it intumesces, and melts into a yellowish 



frothy glass. 



Geological Situation and Localitij, 



It occurs imbedded in Greenstone at Charlestown. 



Remarks. 



Cavities not unfrequently occur in this mineral studded with 

 crystals of Quartz or Epidote. Feldspar often occurs in it, and 



large crystalline grains of white Prehnite are imbedded in the 



green 



