a 
LS LT 
New Cobalt Minerals. 333° 
analysis agrees quite exactly with mine, and leads to the same 
formula of composition. The arsenic-pyritical one has exactly 
the same form as the arsenic-pyrites, and is distinguished from it 
by a reddish color resembling cobalt-glance ; points it directly 
to the composition of arsenical-pyrites, wherein a part of the iron 
is replaced by a quantity of cobalt varying in different individ- 
uals. From the crystals examined by me, I found the follow- 
ing compositions : 
Tron, - - ~ - 30.9 
Cobalt, - ~ - - 47 
the exact mispickel lustre and crystalline form, even to the piers of the ere 
Sp. Gr. = 6.23. The analysis of <— foie two to three unex in | ps 
Sulphur, - 
Arsenic, - - - - - . - = i 
ron, “ S » . - - - 26.54 
Cobalt, - ‘ - - - - - 8.31 
99.97 
but that it aids in forming a strictly chemical compound, inas h € 
replaces the iron. He adds some account likewise of the ee? position of the 
re with reference to the occurrence of the cobalt mine of Skut . This last 
forms a vertical bed, or stratum whose direction is north and a and termin- 
ates Suddenly at the southern declivity of a mountain. Following the direction of 
this stratum nearly a mile, there is found on the opposite side of the Storcte river, 
the cobaltic-arsenical- pyrites bed, having the identical arrangement with that af- 
fording the cobalt glance. It would hence appear that the cobaltic stratum had 
Supplied cobalt to that containing the mispickel as Jong as the metal held out. 
he other variety has a tin or silver lustre, si a Sp. Gr. =6.73. Itoccurs com- 
Pact, with a conchoidal fracture, and a more or less distinet tesseral cleavage : 
. also in g ingle crystals exhibiting octahedral, sabes rhombo-dodecahedral and icos- 
itetrahedral faces. According to ScHEERER, it contained, 
Arsenic, - ue - - - - - 77.84 + 
Cobalt, - a - “ ~ » - 20.01 
Sulphur, - . - “ : " a 0.69 
Tron, i F é si - e n 
Copper, - - . . . ; 
100.05 
Breirnaupr has described this ore under the name of Tesseralkies—Poacenp, 
Ann. d. Phys. B. XLU, 8.546 
The first mentioned ore here pagel is without doubt, the same substance 
Which was noticed at Franconia, N. H., in 1824 by Dr. J. F. Dana of Dartmouth 
College, (Vol. vil, p. 301, this Younsl) Sef icons in 1833 by Mr. A. A. 
