ANNALS 



OF 



PHILOSOPHY. 



FEBRUARY, 1822- 



Article I. 



Amlysis of the Variegated Copper Ore, or Bwitkupfererz. 

 By R. Phillips, FRSE. FLS. &c. 



In looking over the analyses of the various sulphurets of cop- 

 per and iron, 1 was struck not only with the different results 

 obtained by analysts of great experience, but also with the diffi- 

 culty of reconciling any of their statements with the idea that 

 these sulphurets are definite compounds of the ingredients of 

 which they are constituted. That they are of regular composi- 

 tion can, I think, hardly be questioned when specimens from 

 different countries are compared, and especially when it is con- 

 sidered that they are all occasionally met with in the crystalline 

 state ; and have generally different primary forms. 



For the reasons which I have now stated, I propose to examine 

 the native sulphuret of copper and the sulphurets of copper and 

 iron, and with this intention I shall now state the experiments 

 which I have performed upon that which, from accidental causes, 

 first attracted my notice, namely, the variegated copper ore, or 

 buntkupfererz of the Germans. 



This ore is thus described in PhilHps's Mineralogy : 



*' Its colour seems to consist of an intimate mixture of copper 

 red and tombac brown, with an irridescent tarnish, generally of 

 blue, sometimes yellow. The fracture is imperfectly conchoidal 

 occasionally, more often fine grained and uneven ; it is soft, 

 easily frangible, and sectile in a shght degree. Specific gravity 

 5-033." 



On the subject of the crystalline form of this substance, my 

 New Series, v o l . 1 1 1 . g 



