348 Elements of Mineralogy. 



cation. Yet if the black calx be long roafted* 

 it becomes green* which I think arifes from 

 the expulfion of fixed air, which leaves its 

 phlogifton with the manganefe, and thus 

 produces a blue* which mixed with the yellow 

 calx of iron, gives & green; broivn arifes from 

 a mixture of the red and black calces of 

 manganefe. Thefe obfervations I have ex- 

 tra&ed from Ms. Scotch** incomparable differ- 

 tation. 



6. All thefe calces, of whatever colour 

 they may be, communicate a garnet colour 

 to glafs of borax, when treated with a blow 

 pipe, for being melted into a round globule, 

 the furrounding atmofphere dephlogifticates 

 them fufficiently to make them affume this 

 colour. 



7. Hence we may diftinguifh 3 principal 

 varieties of the native calx of manganefe, the 

 white, the red, and the black. 



I. VARIETY. 



White Ore of Manganefe. 



8. This contains but a very fmall proportion 

 of iron 5 it has been found by Mr. Rinman 

 both in fmall white cryftals, and in round 

 mafles in the cavities of quartz and adhering 

 to glanzblend, rather lefs hard than lime- 



ftone, 



