24 PHYSIOGRAPHY. 



Manganblende Manganese Spar. 



MANGANBLENDE. Hexahedral Sclerone- 

 Blende.* 



Primary form. Cube. 



Secondary form. Regular octahedron. 



Cleavage, parallel with the primary form, perfect; traces 

 of cleavage, parallel with its edges. Fracture uneven, im- 

 perfectly conchoidal. Surface rough. 



Lustre imperfectly metallic. Color iron-black. Streak 

 dark-green. Opake. 



Rather sectile. Hardness = 3*5 . . , 4-0. Sp. gr. = 

 4-014. 



Compound Varieties. Massive : composition granular, 

 of various sizes of individuals ; faces of composition irreg- 

 ularly streaked, or rough. 



1. Before the blow-pipe, it is melted with difficulty, and only on its 

 thinnest edges. It emits sulphuretted hydrogen, if reduced to powder, 

 and when thrown into nitric, muriatic, or dilute sulphuric, acid, it is dis- 

 solved. 



2. Analysis. 



By KJLAPROTH. By VAUQUELI^. 



Protoxide of manganese 8200 - - - 85-00 



Sulphur - - - 11-00 - _- 1500 



Carbonic acid - - - 5-00 - - - 0-00 



It is generally, however, considered as a sulphuret of manganese. 



3. It is a rare mineral, ft occurs chiefly in veins along with Black 

 Tellurium, at Nagyag in Transylvania, and in Cornwall. 



4. DEL Rio mentions a variety of Manganblende, found at Oaxaca in 

 Mexico, in which the cleavages are rhornbohedral, and whose sp. gr. = 

 3-8. According to his analysis, it contains 41-7 sulphur, and 58-3 manga- 

 nese. 



MANGANESE SPAR. Tetarto-prismatic Par- 

 a c h r o se-B a ry t e. 



Primary form. Doubly oblique prism. 



