PHYSIOGRAPHY. 195 



Fahlerz Fahlunite. 



2. Analysis. 



By KLAPROTH. 



of Fahlerz. of Schwarzcrz. 



Copper . . 4800 . . 40-25 



Arsenic . . 14-00 . . 0-75 



Antimony . . 0-00 . . 23-00 



Sulphur . . 1000 . . 18-50 

 Iron . . 25-50 . , 13-50 



Silver . . 0-50 . . 0-30 



Other varieties contain the same ingredients in other proportions. 

 Some, moreover, contain zinc, mercury, or lead ; and in some varieties 

 as much as 13 p. c. of silver has been discovered : in others again, a 

 small quantity of gold is detected. 



3. Fahlerz is found in beds and veins. It is accompanied by Copper 

 Pyrites, Spathic Iron, and Quartz. 



4. The varieties of a steel-grey color are found in veins near Frei- 

 berg in Saxony, and in beds in Anhalt in the county of Gomor in Hun- 

 gary, in Stiria, &c. ; varieties called Schwarzerz are met with in veins 

 at Schwatz and other places in Tyrol, at Kapnik in Transylvania, at 

 Cremnitz in Hungary ; also at Clausthal and Andreasberg in the Hartz. 

 It occurs also in the neighborhood of Dillenburg ; in Mansfield ; in small 

 quantities at Airthrie, and other places in Scotland ; in Cornwall, and in 

 South America. 



FAHLUNITE. Peritomous Petaline-Spar. 



Primary form. Oblique rhombic prism. M on M = 

 109 28'. MonP=101 30'. Reniform massive. 



Cleavage parallel to the primary form. Fracture con- 

 choidal . . . uneven, splintery. 



Lustre vitreous. Color olive-green and oil green, pass- 

 ing into yellow, grey, brown, and black. Streak greyish- 

 white. Feebly translucent on the edges . . . opake. 



Hardness =6-0 . . . 6-5. Sp. gr. =2-61 . . . 2-66. 



1. Before the blow-pipe, it becomes pale-grey, and melts on its thin- 

 nest edges. It is but slowly dissolved in glass of borax, and communi- 

 xates to it the 'color produced by oxide of iron. 



