oj Boston and its Vicinity. 1^8 



It is amorphous. 



It adheres slightly to the tongue. 



Its soil is brownish red. 



The streak is deep reddish orange. 



The fracture is fine grained uneven, passing into earthy, and 

 is straight foliated, with a threefold cleavage, parallel to the faces 

 of a rhomboidal prism. 



It is brittle. 



It is easily frangible. 



The fragments are imperfectly rhomboidal, and indetermin- 



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ately angular and sharp-edged. 



Its specifick gravity is about 3.230. 



Chymical Characters. 

 Before the blowpipe it becomes blackish brown and magnetick 



dark green colour, 



be. 



fused with borax, communicates to it a 



tween blackish green and olive green. It feebly effervesces in 

 nitrick acid. 



Geological Situation and Locality. 

 It occurs massive in rounded fragments of Quartz, in Cam- 



bridge. 



It is accompanied with the sulphuret and ochrey brown Oxide 



of Iron. 



Me marks. 



By long exposure to the weather, the fracture and fragments 



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of this mineral, which serve to distinguish it from the compact 

 brown Oxide of Iron, become indistinct, and rhomboidal fragments 

 are not easily obtained. 



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