30 PHYSIOGRAPHY. 



Antimonial Silver. 



Cleavage parallel to o and P distinct ; cleavage parallel 

 to M imperfect. 



Fracture uneven. 



Surface in general smooth. 



Lustre metallic. Color silver-white, inclining to tin- 

 white. Streak unchanged. 



Hardness = 3-5. Sp. gr. = 9-44 . . . 9-8. 



Compound Varieties. - Twin-crystals like those of Ar- 

 ragonite and White Lead-Ore. Massive : composition 

 granular, individuals of various sizes, and easily separated. 



Pseudomorphic six-sided prisms. 



1. Before the blow-pipe, it yields a globule of silver, while the anti- 

 mony is driven off. 



2. Analysis. 

 Silver - ... . 76-5 



Antimony 23-5 



3, It is found accompanied by Native Silver, Native Arsenic, Galena 

 and various other species. Its localities are Altwolfach in Fiirstenberg, 

 and Andreasberg in the Hartz. 



4. The Arsenical Silver is considered as a more or less intimate me- 

 chanical mixture of Native Arsenic, or of Mispickel with Antimonial Sil- 

 ver. It possesses the color of Native Silver, hut is commonly tarnished 

 externally of a blackish color. It occurs in small, curved lamellar com- 

 positions, consisting of very thin crystalline coats. It is harder than An- 

 timonial Silver. Before the blow-pipe, the arsenic and antimony are for 

 the most part volatilized, leaving a globule of impure silver, surrounded 

 by a slag. A specimen from Andreasberg afforded Klaproth, 



Arsenic - - - - 35-00 



Antimony ..... 4 00 



Silver 12-75 



Iron 44-25 



Its localities are the same as those mentioned for Antimonial Silver, 

 and in addition, it comes from Guadalcaual in Estremadura in Spain, 



5. It is valuable for the extraction of silver. 



ANTIMONY PHYLLITE. 



Primary form. Rhombic prism. Dimensions unknown, and like- 

 wise whether the prism be right or oblique. 



