the Ores of Manganes 127 



Manganite occurs in very few places. It is found in great 

 abundance, often beautifully crystallized, in the manganese mines 

 of Ihlefeld in the Hartz, occurring in veins traversing porphyry. 

 Thin crystals and masses consisting of columnar individuals, when 

 rubbed down on a plate of porcelain biscuit, in order to ascertain 

 the colour of their streak, frequently yield a black powder at 

 first, the characteristic brown tint appearing only when a consi- 

 derable portion of the whole has been rubbed off. At Ihlefeld 

 Manganite is associated with calcareous spar, and heavy-spar, 

 particularly with the latter. The specimens analyzed, which 

 likewise have yielded Figs. 5, to 10, described above, were found 

 at Ihlefeld, and were brought by Dr TURNER from Germany. 

 The same species occurs in gneiss, occasionally traversing it in 

 small irregular veins and mixed with quartz, at Granam in Aber- 

 deenshire. It is found likewise at Christiansand in Norway, and 

 Undenaes in Westrogothia in Sweden. A massive variety of 

 manganite, consisting of small spicular crystals with many drusy 

 interstices, is found in Nova Scotia. 



II. PYRAMIDAL MANGANESE-ORE. 

 Hausmannite. 



Blaettricher Schwarz-Braunstein, Hausmann, p. 293. 

 Foliated Black Manganese-ore, Jameson, vol. iii. p. 263. 

 Black Manganese, Phillips, p. 381. 

 Pyramidales Mangan-erz, Molts, vol. ii. p. 484. 



Pyramidal Manganese-ore, Mohs, Trans, vol. ii. p. 416. Id. Haidinqer, Edin. 

 Journ. of Science, vol. iv. p. 46. 



Schwarz-Manganerz, Leonhard, p. 760. 



''KJ H Ml ftOi 



Fundamental form. Isosceles four-sided pyramid. 

 P = 105 25', 117 54'. Fig. 14. 



a = V2.76. 



