PHYSIOGRAPHY. 257 



Herderite Herrerite. 



the faces p and t, the former being smooth, or but faintly streaked par- 

 allel to their intersections with P, while the latter are granulated, proves 

 that the forms do not belong to the hexagonal, but to the prismatic sys- 

 tem. 



2. The only specimen of Herderite at present known, is in the Wer- 

 nerian museum at Freiberg. It came from the tin-mines of Ehrenfrie- 

 dersdorf in Saxony. 



HERRERITE. Staphyline Tellu rium-Baryte. 



Massive : in reniform masses. 



Cleavage in three directions, affording rhomboidal frag- 

 mentSj whose angles are incapable of measurement on ac- 

 count of the curvatures of the faces. 



Lustre vitreous to pearly, and shining, on fresh surfaces. 

 Color pistachio, emerald, and grass-green. Streak yellow- 

 ish grey. Translucent. 



Brittle. Hardness =4-0 . . . 4-5. Sp. gr. =4-3. 



1. Before the blow-pipe, on charcoal, it at first becomes grey, and af- 

 terwards gives a white smoke, which adheres to the charcoal. On di- 

 recting the reduction flame of the blow-pipe upon it, it becomes of a 

 beautiful grass-green. Heated in an open tube, it gives an abundant 

 white smoke, which adheres to the glass, and on examining it with a 

 microscope, it is seen to be composed of innumerable white and transpa- 

 rent globules. 



2. Analysis. 

 By HERRERA. 



Carbonic acid . . . . 81-86 



Tellurium .... 55-58 



Peroxide of nickel .... 12-32 

 3. It is found at Albarradon in Mexico, in transition limestone, in a 

 metallic vein, consisting chiefly of ores of lead, Native Silver, Horn- 

 Silver, and lodic-Silver. 



APPENDIX TO HERRERITE. 

 i. Fibrous Herrerite. DEL Rio, 



Massive : reniform, composition columnar, individuals slender 

 and radiating. Earthy and dull. 



22* 



