Fig. 15 Photomicrograph of pyritiferous pegmatite, Farr mine, with branching 

 veinlets of pyrite cutting several individuals of quartz without disturbance of optical 

 orientation. Crystal boundaries of pyrite, very sharp. (Magnified 27.5 diameters) 



Fig. 17 Ore, Stella mine. A rather fin^. pranular aggregate of pyrite, chlorite, 

 graphite, quartz and feldspar. (9/10 natural size) 



