246 



COBALT. 



738. SMALTITE. (Grey Cobalt Ore, Tin White Cobalt.) 



a. Crystalline. 



Note. This mineral is a mixture of the arsenates of cobalt, iron, and 

 nickel, with traces of copper. See Dana, Mineralogy, p. 70. 



MANGANESE. 



739. PYEOLUSITE. (Prismatic Manganese Ore, Gray Oxide of Man- 



ganese.) 



a. In small masses, having a radiate structure and metallic 



lustre. (Polianite.) 

 Z>. Ditto, impure. (Varvicite.) 

 Note. See Dana, Mineralogy, pp. 166-171. 



740. MANGANITE. (Hydrated Oxide of Manganese.) 



a. Massive. 



Note. Manganite gives a brown or brownish-black streak, pyrolusite 

 an almost pure black or a bluish-black streak. See Dana, Mineralogy, 

 p. 170. 



741. PSILOMELANE. (Black Haematite, Black Iron Ore, Compact Black 



Manganese Ore.) 

 a. Massive. 



Note. This mineral also gives a brownish-black streak, but is much 

 harder than manganite. It usually contains manganese and barium 

 oxides, with occasional traces of other metals. See Dana, Mineralogy, 

 p. 180. 



742. RHODONITE. (Bisilicate of Manganese, Red Manganese.) 



a. Massive. 

 Note. For description, etc., see Dana, Mineralogy, p. 225. 



ANTIMONY. 



743. ANTIMONITE. (Stibnite, Antimony Glance, Sulphuret of Antimony.) 



a. A large specimen. 



b. A smaller specimen, from Borneo. 



c. Separated from the 'quartz by fusion. 



d. French regnlus of antimony. 



Note. Specimen d is an original, almost hemispherical cake, and has 

 a crystallized surface. For fig. of crystal of antimonite and description, 

 see Dana, Mineralogy, p. 29. 



ARSENIC. 



744. REALGAR. (Red Sulphuret of Arsenic, Sandaraca, Germ.) 



a. Crystallized. 



Note. This specimen is slightly altered, to orpiment and arsenious 

 acid, by exposure. See Dana, Mineralogy, p. 27. 



