PHYSIOGRAPHY. 147 



Copper Mica. 



Secondary form. 



The annexed figure is the pri- 

 mary, having the summits repla- 

 ced by single planes. Tingtang, Cornwall. 



Cleavage, parallel with P, or the primary, only in traces; 

 but parallel with o, with great ease. Surface, o smooth, 

 sometimes striated in triangular directions. P often a little 

 uneven. 



Lustre pearly upon o, both as faces of cleavage, and as 

 faces of crystallization. The faces P possess a lustre in- 

 termediate between vitreous and adamantine. Color, em- 

 .erald-green and grass-green. Streak emerald-green to 

 apple-green, rather paler than the color. Transparent . . . 

 translucent. 



Sectile. Hardness =2-0. Sp. gr. = 2*5488. 



Compound Varieties. Massive : composition granular 

 of various sizes of individuals ; faces of composition uneven 

 and rough. 



1. Before the blow- pipe, it loses both color and transparency, emits 

 fumes of arsenic, and is changed into a friable scoria, containing some 

 white metallic globules. With borax it yields a green globule, and is 

 partly reduced. In nitric acid, it is soluble without effervescence. - 



2. Analysis. 

 By CHENEVIX. 



Oxide of copper . . . 49-00 



Arsenic acid . 14-00 



Water . 35-00 



3. The present species occurs in copper veins, along with various 

 other ores of copper, particularly with the Liroconite, and with Brown 

 Iron-Ore and Quartz. 



4. It is found only in some of the copper mines near Redruth in Corn- 

 wall ; and in minute crystals at Herrengrund in Hungary. 



