<6 THE PROSPECTOR'S HANDBOOK. 



Streak blackish grey, sometimes shining. 

 H. 2-5 to 3; S.S. 5-5 to 5-8. 



Composition per cent. sulphur, 20'6 ; copper, 77 '2 : 

 iron, 1*5. 



Before the blowpipe gives off sulphur fumes, fuses easily 

 in the outer flame, and boils, leaving a globule of copper. 

 Is fusible in a candle flame. Is rather like sulphide of silver, 

 but the button left after exposure to B.F. shows the differ- 

 ence. If the mineral be dissolved in nitric acid, and the 

 point of a penknife be placed in it, a slight copper coating 

 will be formed if the metal is present, whereas, if a piece of 

 bright copper be placed in it, a slight coating of silver will 

 be formed if silver be present. 



Copper Pyrites (chalcopyrite). 



Crystallization tetrahedral, also massive, &c. 



Colour brass yellow, sometimes tarnished and iri- 

 descent. 



Streak greenish black and unmetallic. 



H. 3-5 to 4 ; S.G-. 4'15. 



Composition per cent, sulphur, 34-9; copper, 34'6 ; 

 iron, 30-5. 



In a glass tube closed at one end it decrepitates, and a 

 sulphur sublimate is left. 



Before the B.F., it fuses to a metallic globule. If fused 

 with borax, metallic copper is the result. Tested in acid, 

 like other copper ores. Is sometimes mistaken for gold, 

 iron pyrites, or tin pyrites; but it crumbles when cut, 

 whereas gold can be cut in slices. Is of a deeper colour 

 than iron pyrites, and yields easily to the knife, nor does it 

 strike fire like iron pyrites. It may be distinguished from 

 tin pyrites by the blowpipe and other tests. If the ore be 

 hard and of a pale yellow colour, it is considered to bo poor 

 in copper. 



Variegated copper pyrites (containing 60 per cent, of 

 copper) is of a pale reddish yellow colour. 



Grey Copper (tetrahedrite). 



When containing silver, Fahlerz. 

 Crystallization tetrahedral, &c. 



