30 



The Ottawa Naturalist. 



tfcata cf JncAcs 



Crystals of Huronite in Diabase. 

 i ii No. 995, Geological Survey of Canada Museum) 



From % mile N. of Murphy Lake, Algoma, Ont. 



The name " Huronite " has usually been restricted to yellowish 

 green more or less rounded masses or phenocrysts, which rarely 

 exceed two inches in diameter, embedded in a medium textured dark 

 greenish or greyish groundmass. Many of the smaller and not a few of 

 he larger individuals have an irregular or jagged outline owing to mag" 

 matic corrosion and frequently exhibit small arms or bays which have been 

 filled by the invading magma. Occasionally some are seen with a 

 more or less perfect crystallographic outline and many exhibit one or 

 more sharp crystal faces. The mineral is light yellowish-green in 

 colour although portions of the crystals which hive undergone less 

 alteration show a very pale flesh red or pink colour as in the case of 

 the Murphy Lake and Eastmain specimens. The crystals weather 

 to an opaque greyish-white forming very conspicuous spots in an other- 

 wise dark coloured rock. Under the microscope the greenish colour 

 is seen to be due to the more or less abundant development of 





