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dull metallic lustre, and a colour something between that of 

 ordinary Pyrites and of Copper, or, more like Kupfernickel. 

 This colour is observed, as a rule, only in the freshly-fractured 

 surface, as the speedy tarnish of this mineral soon leaves its 

 exterior of a various duller tints, ranging to umber-brown, with 

 traces here and there of seme faint iridescence. 



The lamellae exhibit curved faces in some instances; but whether 

 the curvature is due to original crystallization, or to subsequent 

 disturbances affecting the mass, does not seem quite clear. 



J. G. G. 



G, AND T. COWARD, PRINTERS, CARLISLE. 



