Copper. 257 



SPECIES I. 



Native. 



d. Native copper, that is copper hi a more 

 or lefs malleable itate, and either of its own 

 peculiar, onof a grey or blackifh colour, has 

 been found either in grains, or in large fhape- 

 lefs folid lumps, or in a foliated, capillary, 

 arborefcent form, or cryftalized in quadran- 

 gular pyramids, in or on clay, fhiftus, quartz, 

 fluors, zeolytes, &c. in Siberia^ Sweden^ Ger- 

 ^ Hungary, Tranfyfoania, &c. 



3. It undoubtedly has fometimes been pro- 

 duced from precipitation by iron from wa- 

 ters in which it was held in folution, and this 

 is the purefl fort, but in many cafes it could 

 not have been produced in that manner, and 

 then this fort is never very pure, but mixed 

 either with gold, filver, or iron, or with ful- 

 phurs this laft combination forms what is 

 called black copper* 



4. All thefe impurities are difcoverable by 

 folution, in nitrous acid ; the gold remains 

 undiffolved in the form of a black powder, 

 foluble in aqua regia ; the filver may be pre- 

 cipitated by the marine acid, or ftill better by 

 .a clean polifhed plate of copper, the iron is 



S feparated 



