150 PHYSIOGRAPHY. 



Lustre vitreous, inclining to adamantine on the 

 surface, and to resinous in the interior. Colour 

 principally leek-green, which passes almost into 

 white, or also into olive-green and liver-brown. 

 Streak white. Semi-transparent ... translucent 

 on the edges. 



Rather brittle. Hardness = 3-5 ... 4-0. Sp. Gr. 

 = 3-162. 



Before the blowpipe it emits an arsenical odour, and melts 

 into a reddish-brown scoria, which acts upon the magnet, 

 If it has been heated long enough to drive off' all the arsenic. 

 According to FICINUS, it consists of 



Arsenious Acid 31-40. 



Sulphuric Acid 1-54. 



Water 18-00. 



Protoxide of Iron, with Magne- \ 

 sia, Lime, and Manganese / 

 It occurs in primitive mountains at Schwarzenberg in 

 Saxony with prismatic Arsenical-pyrites, at Lb'ling near 

 Hiittenberg in Carinthia with axotomous Arsenical-pyri- 

 tes ; it is accompanied in the latter place also by octahedral 

 Bismuth and brachytypous Parachrose-baryte. Beautiful 

 specimens have lately been brought from Brazil. It occurs 

 in several of the Cornish mines. The Martial Arseniate of 

 Copper from Cornwall seems to be merely a variety of the 

 Scorodite. It consists, according to CHENEVIX, of oxide 

 of copper 22-5, arsenic acid 33-5, oxide of iron 27 '5, water 

 12*0, and silica 3-0. 



SELENIURET OF COPPER. ; -:Q 



Cuivre se'le'nie. HAUY. Traite', 2de Ed. T. III. p. 469. 

 Seleniuret of Copper. PUILL. p. 304. 



Massive ; also superficial upon fissures in rhombo- 

 hedral Lime-haloide. 





