336 Etemehts of Mineralogy. 



SPECIES II. 

 Mineralized by the aerial acid. 



Stack Ochre of Cobalt, Vitreous Ore ofCobatti 

 Kobalt miilm, Schtaken-Kobatt. 



3. This appears either in a loofe, powdery 

 form, fometimes as fine as lamp black, either 

 grey or bkckim, and called cobalt oehre, or 

 in black indurated fcoriform maflesj called 

 Schlaken Kobalt, or vitreous cobaltic ore : 

 they are both commonly free from fulphur 

 and arfenic, and wheti there are any, they 

 are only mechanically mixed with this ore ; 

 fome fmall proportion of copper and iron is 

 alfo fomdtimes found in it ; it is frequently 

 imbodied in ftones or fands of a black co- 

 lour 5 talc, chalk and gypfum impregnated 

 with it have been called by the fame name* 

 and by fome Spiegel Cobalt ; it is alfo con- 

 tained in fome green and blue earths as al- 

 ready mentioned, p. 78, and 79* 



4. Toanalyfe this ore let it be diflblved in 

 the nitrous acid ; a plate of copper dipped in 

 the folution will difcover and precipitate the 

 filver, if any, and a plate of iron will dif- 

 cover and precipitate copper, if the folutioa 

 contains any ; but it mould fpeedily be with- 

 drawn left the cobalt alfo ihould be precipi- 

 tated ; 



