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143 



Outlines of the Mineralogy and Geology 



It is easily frangible. 



The fragments are rhomboidal. 



Its specifick graTity is about S.33S 



Chymical Character 

 It is infusible before the blowpipe. 



Geological Situation and Localities. 



'i> 



It occurs (lissemiiialed and in small veins in Argillite at Charles- 

 town ; and in Amygdaloid at Brighton. 



Variety II, — Laminated Calcareous Spar. 



External Characters, 



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

 milk white and yellowish white ; of grey, ash grey and greenish 

 grey ; of green, it occurs blackish green. 



Its lustre alternates from splendent to shining and glistening ; 

 and is vitreous inclining to pearly. 



It is translucent at the edges and in thin lamina transparent. 

 It is amorphous and in amygdaloid shaped pieces. 

 The streak is whitish. 

 It is serai-hard. 



The fracture is perfectly straight foliated, with a threefold 

 cleavage parallel to the sides of a rhomboidal prism ; some speci- 

 mens present a fine splintery fracture. 



J'^ 



It is brittle. 



It is easily frangible. 



The fragments are perfectly rhomboidal. 

 Its specifick gravity is about S.737. 



w -M 



