418 PHYSIOGRAPHY. CLASS II. 



2. UNCLEAVABLE MANGANESE-ORE. 



Compact and fibrous Manganese-Ore or Black Hema- 

 tite. JAM. Syst. Vol. III. p. 261. 262. Prismatic 

 Manganese-Ore or Black Manganese-Ore (in part). 

 Man. p. 255. Black Iron-ore (in part). Compact Grey 

 Oxide of Manganese. PHILL. p. 232. 244. Schwarz- 

 eisenstein. WERN. Hoffm. H. B. III. 2. S. 270. Fas- 

 riger and dichter Schwarzbraunstein. HAUSM. I. S. 

 293. 294. Dichtes Schwarz-Manganerz. LEONH. S. 

 374. Manganese oxyde noir-brunatre ? I IAU Y. Tabl. 

 comp. p. 110. Manganese oxyde hydrate' coneretion- 

 nd Traite, 2de Ed. T. IV. p. 267- 



Regular forms and cleavage unknown. Fracture 



not observable. 

 Lustre imperfect metallic. Colour, blueish- black 



and greyish-black, passing into dark steel-grey. 



Streak brownish-black, shining. Opake. 

 Brittle. Hardness 5-0... 6-0. Sp. Gr. = 4- 1 45, 



a botryoidal variety. 



Compound Varieties. Heniform, botryoidal, 

 fruticose : composition columnar, impalpable ; frac- 

 ture flat conchoidal, even ; in a second composition 

 it is curved lamellar, the faces of composition being 

 smooth, rough, or granulated. Massive : compo- 

 sition granular, impalpable, strongly connected, 

 fracture flat conchoidal, even. 



OBSERVATIONS. 



1. The tw& subspecies of Slack Iron-Ore, the Fibrous 

 Black Iron-Ore, or Black Hematite, and the Compact Black 

 Iron-Ore, differ from each other like the analogous varie- 

 ties of rhombohedral and prismatic Iron-ore, or as Red 

 and Brown Hematite differ from compact Red and Brown 

 Iron-ore. 



2. The mixture of the uncleavable Manganese-ore has 



