416 PHYSIOGBAPHY. CLASS ir. 



Oxide of Iron 55 00. 



Silica 28-00. 



Lime 12-00. 



Oxide of Manganese 3-00. 



Alumina 0-60. 



After having been exposed to heat, it acts on the magnetic 

 needle. Before the blowpipe it melts easily and without ef- 

 fervescence into an opake glass, which is likewise magnetic. 

 Glass of borax is coloured by it yellowish-green. It is so- 

 luble in muriatic acid. 



2. The present species is found in beds in primitive rocks, 

 along with paratomous and prismatoidal Augite-spar, with 

 dodecahedral Garnet, rhombohedral Quartz, octahedral 

 Iron-ore, &c. 



3. Its chief locality is the island of Elba, where it is 

 found in crystals sometimes of considerable size ; but it has 

 been discovered also at Kupferberg in Silesia, at I'ossam 

 in Norway, in Siberia, and in North America. 



GENUS XI. MANGANESE-ORE. 

 1. PYRAMIDAL MAXGANESE-ORE. 



Foliated Black Manganese- Ore. JAM. Syst. Vol. III. 

 p. 263. Black Manganese. PHILL. p. 381. Schwarzer 

 Braunstein. WERN. Hoffm. H. B. IV. 1. S. 149. 

 Bliittriger Schwarz-Braunstein. HAUSM. I. S. 293. 

 Manganese oxyde hvdrate. HAUY. Traite', 2de Ed. 

 T. IV. p. 2G4. 



Fundamental form. Isosceles four- sided pyramid. 

 P = 105 25', 117 54'. Vol. I. Fig. 8. Ar. 



a = V 2 '7C. 

 Simple forms. |P 4 (a) = 139 56', 58 46'; 



P 1 = 114 51', 99 11' ; 1* (P). 

 Char, of Comb. Pyramidal. 



