PHYSIOGRAPHY. 



Euchroite. 



189 



3. From the foregoing description, Erlan would appear to be only a 

 variety of argillite. 



ESSONITE. (See Garnet.) 



iUCHROITE. Peritomous C o p p e r-Baryte. 

 Primary form. Right rhombic prism. M on M=117 



|20'. 



Secondary form. 

 M on M 

 / on I 

 s on s 

 ?i on n 



Cleavage, parallel to the primary lateral planes, distinct; 

 indistinct parallel to n. 



Fracture small conchoidal, uneven. Surface, the verti- 

 al faces of the prism streaked parallel to their common 

 dges of combination. 



Lustre vitreous. Color bright emerald-green. Streak 

 >ale apple-green. Double refraction considerable. Trans- 

 arent . . . translucent. 



Rather brittle. Hardness = 3-5 ... 4-0. Sp, gr. = 

 3-389. 



1. In the matrass, it loses its water, and becomes yellowish green and 

 riable. When heated to a certain point upon charcoal, it is reduced in 

 n instant with a kind of deflagration, leaving a globule of malleable cop- 

 er, with white metallic particles dispersed throughout its mass, which 

 re entirely volatile upon a continued blast. 

 2. Analysis. 

 By TURNER. 



Peroxide of copper . . . 47-85 

 Arsenic acid . . . 33-02 



Water . . 18-80 



S. It was discovered at Libethen in Hungary, in quartzose mica slate. 



