PHYSIOGRAPHY. 



Hopeite Hornblende. 



261 



Sectile. Hardness =2-5 . . . 3-0. Sp. gr. =2-76. 



1. Before the blow-pipe, it gives off its water, and melts into a clear 

 colorless globule, tinging the flame green. It gives no skeleton of silica 

 with salt of phosphorus, with which it melts in all proportions. If much 

 of the mineral is added, the globule turns opake in cooling, but dees not 

 deposit any fumes of zinc on the charcoal. The globule obtained from 

 'using it with borax does not become opake on cooling. With soda, it 

 gives a scoria which is yellow when hot ; copious fumes of zinc, and 

 nearest the scoria, some of cadmium also, are deposited. The melted 

 mineral forms a fine blue glass with solution of cobalt. Hopeite seems 

 therefore to be a compound of some of the stronger acids, as phosphoric, 

 or boracic acid, with zinc an earthy base, a little cadmium, and a great 

 deal of water. 



2. It has been hitherto found only in the Calamine mines of Alten- 

 berg, near Aix-la-Chapelle, and is very rare. 



HORNBLENDE. Hemi-prismatic Augite-Spar. 

 MOHS. 



Primary form. Oblique rhombic prism. M on M'= 

 124 30'. 



Secondary forms. 



Fig. 243. Fig. 244. 



M 



M 



M 



.M 



Edenville, (N.Y.) 



Edenvflle and Amity, (N.Y.) 



