THE NONMETALLIC MINERALS. 



187 



The mineral occurs in o-neiss in Sweden; with barite and siderite at 

 Miisen; in limestone with galena and dolomite at Mine La Motte, 

 Missouri, and with sulphides of iron and copper in chloritic schists in 

 Maryland. 



Sychnodymite has the formula (Co, Cu)^ S.,, and yields sulphur, 

 ■10.04 per cent; copper, 18.98 per cent; cobalt, 35.79 per cent; nickel, 

 3.66 per cent; iron, 0.93 per cent. It is of a steel-gray color, metallic 

 luster, and has a specific gravity of 4.75. 



Erythrite or cobalt bloom (Specimens Nos. 17698, 51909, 56463, 

 63096, and 67759, U.S.N.M.) is the name given to a hydrous cobalt 

 arsenate of the formula CogAsjOg+SHaO, = arsenic pentoxide, 38.4 

 percent; cobalt protoxide, 37.5 per cent, and water, 24.1 per cent. 

 It occurs in globular and reniform shapes and earthy masses of a 

 crimson to peach-red color associated with the arsenides and sulphar- 

 senides mentioned alwve and from which it is derived by a process of 

 oxidation. In Churchill County, Nevada, it occurs as a decomposition 

 product of a cobalt bearing niccolite. It is also found at the Kelsey 

 mine, Compton. in Los Angeles County, California; associated with 

 cobaltite at Tambillo and at Huasco, Chile, and under similar con- 

 ditions in various p.rts of Europe. 



AsBOLiTE, or earthy cobalt (Specimen No. 60993, IT. S.N. LI.), is a 

 black and earth}' ore of manganese (wad) which sometimes carries as 

 high as 30 per cent of cobaltic oxide. It takes its name from the Greek 

 aaftokaivoD^ to soil like soot. Roselite is an arsenate of lime, mag- 

 nesia and cobalt with the formula (Ca, Co, Mg)3As20g, 2H2 O, = arsenic 

 pentoxide, 51.4 per cent; lime, 28.1 per cent; cobalt protoxide, 12.5 per 

 cent; water, 8 per cent. It is of a light to dark rose-red color, hardness 

 3.5; specific gravity 3.5 to 3.6, and vitreous luster. Sph^erocobaltite 

 is a cobalt protocarbonate of the formula C0CO3, = carbon dioxide, 37.1 

 per cent; cobalt protoxide, 62.9 per cent. It is also of a rose-red color, 

 varying to velvet black. Hardness 4, and specific gravity 4.02 to 4.13. 

 It occurs but sparing, associated with roselite at Schneeberg in Saxon}^ 

 Remixgtonite is a hydrous carbonate the exact composition of which 

 has not l)ecn ascertained. Cobaltomenite is a supposed selenide of 

 cobalt. Bieberite, or cobalt vitriol, is a sulphate of the formula 

 CoSO^ + 7 H.^O. The color is flesh to rose red. It is soluble in water, 

 has an astringent taste, and occurs in secondary stalactitic form. 

 Pateraite is a possible molybdate of cobalt. 



Aside from the possible sources mentioned above, cobalt occurs 



