350 Elements of Mineralogy. 



nefe, as they contain more of it than of 

 iron. 



II. VARIETY. 



Red Ore of Manganefe* 



12. It contains lefs fixed air, and is accom- 

 panied with more iron than the former va- 

 riety, and alfo with calcareous or ponderous 

 earth and filex. It is found either loofe and 

 iemi-indurated in a matrix of calcareous fpar, 

 or talky fhiftus, or on hsemetites and other 

 iron ores, or in heavy hard mafles of a lamellar, 

 radiated, or equable texture, or cryftalized in 

 pyramids, rhomboids, QV {hort bright brittle 

 needles. 15. Roz. 6.9, 



III. VARIETY. 



Slack and Brown Ore of Mangctnefe. 



13, I place thefe together, as they differ- 

 but little ; they are found either cryftalized ia 

 the fame form as the red ore, or in folid; 

 mafles, fome of which have a metallic ap- 

 pearance, others are dull, earthy, and mixed 

 or embodied with quartz, or in a loofe earthy 

 form ; their fpecific gravity is about 4,000 

 both, particularly the brown and the red arc 

 foluble in fome meafure by digeftion in oil of 

 vitriol, and the folution is at firft reddifh, but 



afterwards 



