THE NONMKTALLIO MINKHALS. 185 



Tn Saxony thomincnil (SpociuuMis Nos. (MY.)'2'2 aiul r»7T:>(), U.S.N. M.) 

 occurs in lodes in o-iiciss and in wiiich heavy spar (haivte) forms the 

 characteristic gant»'ue. It is associated witii other metallic sulphides, 

 notably those of lead and cop})er. At Skutterud and Snarum, Nor- 

 way, the cobaltiferous fahlbands, accordinu- to Phillips' 



Occur in crystalline roekn varying in character between gneiss and mica schists, ))nt 

 from the presence of hornblende they sometimes pass into iiorn blende schists; among 

 the accessory minerals are garnet, tourmaline, and graphite. These schists, of which 

 the strike is north and south, and which have an almost perpendicular dij), contain fahl- 

 bands very similar in character to those of Kongsberg. They differ from those of that 

 locality, however, inasnuich as while here the fahlbands are often suftieiently impreg- 

 nated with ore to pay for working, those of Kongsberg, although to some extent contain- 

 ing disseminated sulphides, are only of importance as zones of enrichment for ores 

 occurring in veins. The ore zones usually follow the strike and dip of the surround- 

 ing rocks, and vary in breadth from 2^ to 6 fathoms. The distribution of the ores is 

 by no means equal, since richer and poorer layers have received special names and 

 are easily recognized. The Erzbander, or ore bands, are distinguished from the 

 Reicherzl)ander, or rich ore bands, while the bands of unjiroductive rock are known 

 as Felsbander. The predonnnant rock of the fahlbands is a quartzose granular mica 

 schist, whicli gradually passes into quartzite, ordinary mica schist, or gneiss. The 

 ores worked are cobalt glance, arsenical, and ordinary pyrites containing cobalt, 

 skutterudite, magnetic iron pyrites, copper pyrites, molybdenite, and galena. It is 

 remarkable that in these mines nickel ores do not accompany the ores of cobalt in 

 any appreciable quantity. The principal fahlband is known to extend for a distance 

 of about 6 miles, and is bounded on the east by a mass of diorite which protrudes 

 into the fahlband, while extending from the diorite are small dikes or branches 

 traversing it in a zigzag course. It is also intersected by dikes of coarse-grained 

 granite which contain no ore, but which penetrate the diorite. 



The Skutterud mine in 1879 produced 7,700 tons of cobalt ore, which yielded 108 

 tons of cobalt schlich (concentrates), containing from 10 to 11 per cent of cobalt, 

 and worth about £11,000. 



At Dacshkessan the ore occurs under a sheet of diabase, the cobaltite 

 being in the wall rock of this sheet, and which carries also garnets and 

 copper pyrites. In 1887, 1,216 kilograms of the mineral were extracted; 

 in 1888, 5^28 kilograms, and in 1889, 12,960 kilograms, besides some 

 3,000 kilograms of cobaltiferous matter obtained in treating the cobal- 

 tiferous copper ores.'"^ 



Smaltite. — (Specimen No. 66757, U.S.N.M.) This is essentially 

 a cobalt diarsenide of the formula CoAsg, = arsenic, 71.8 per cent; 

 cobalt, 28.2 per cent; hardness, 5.5 to 6; specific gravity, 6.-1 to 6.6. 

 Color, white to steel gray. Through the assumption of nickel the min- 

 eral passes b}^ gradations into chloanthite. 



^Ore Deposits, by .f. A. Phillips, p. 389. '^ Annales des Mines, II, 1892, p. 503. 



