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NEW YORK STATE MUSEUM 



Vein type of graphite. Quite distinct from the bedded deposit 

 is the occurrence of several true fissure veins of quartz carrying 

 foliated graphite. They without doubt represent the last dying 

 phases of the igneous activity of the Algoman granite. These 

 veins are chiefly of hydrothermal deposited quartz that cut through 

 the schists and quartzites in a most irregular way. Bordering the 

 edges of these veins of pure milky quartz, the fibrous graphite is 

 arranged in rosettes and spherulitic forms as a fringe, often an 

 inch in width. One of them cuts diagonally across the trench so 

 that it is exposed on both sides. A detailed drawing of this par- 



Nil LUNETER 

 IGRAPHITE 



iDIOPSIDE 



PYRITE 

 QUARTZ 



Fig. 19 Camera-lucida drawing of microscopic thin 

 section of the " high-grade " Rowland ore, showing 

 the graphite flakes embedded in diopside. H. L. 

 Ailing, 1918. 



ticular one is here given. It has been stated that two more veins 

 were found in the shaft and drift. " The mine superintendent stated 

 that in 1899 one piece of nearly pure graphite weighing 543 pounds 

 was taken out." 1 



Exceedingly attractive specimens may be collected from the 

 dump ; they are so striking that it is not surprising that they have 



1 Miller, W. J., N. Y. State Mus. Bui. 170, p. 82. A chemical analysis by H. 

 F. Gardner gives 82.72 per cent graphite carbon for the vein type of graphite. 



