3C8 Mr. T. S. Hunt's Examinations of some Fehpathic Rocks. 



The hypersthene occurs in foliated masses with curved sur- 

 faces. Besides the basal cleavages thus exhibited, it cleaves 

 readily with the sides of an oblique prism of 87°, and with its 

 longer diagonal. The hardness of the mineral is 6, and its 

 density 3409 to 3*417. Lustre vitreous, submetallic ; colour 

 blackish-brown, in thin laminse yellowish-brown ; streak and 

 powder ash-gray, the powder turning reddish-gray on ignition. 

 Subtranslucent, brittle, fracture uneven. The fragments which 

 had served to determine the density still contained flakes of fels- 

 pathic matter between the laminae ; these were, as far as possible, 

 removed in breaking up the hypersthene for analysis. The 

 results of two analyses by fusion with carbonate of soda were as 

 follows : — 



99-66 99-98 



It is almost identical in composition with the hypersthene 

 from Labrador, analysed by Damour. 



The accompanying ilmeiiite was more or less interpenetrated 

 with felspar and quartz, which could not easily be separated. Its 

 hardness was 6, and the density of selected fragments from 4-65 

 to 4-68. Colour and streak iron-black, lustre submetallic ; not 

 magnetic. When decomposed by fusion with bisulphate of 

 potash, it gave, — 



VII. 

 Titanic acid .... 3986 

 Peroxide of iron . . . 56-64 



Magnesia 1:44 



Insoluble quartz, &c. . 4 - 90 



102-84 



A large portion of the iron is to be regarded as protoxide. 



Another variety of the lime-felspar rock from Chateau-Richer 

 is pale greenish or bluish-gray, with occasional reddish grains, 

 and is finely granular. The lustre is vitreous upon the cleavages, 

 but waxy elsewhere. The only foreign mineral observed in the 

 rock was brownish-black mica in small scattered patches. The 

 density of the greenish-gray portion was 2-681, and its analysis 

 gave,— 



