Dr. Genth’s Contributions to Mineralogy. 419 
_ I may state that I have also observed this mineral at the 
Springfield Mine, Carroll County, Md. from which locality I 
have an octahedral erystal. 
~ In Prof. J. D. Dana’s Mineralogy the formula is written 
€uS + Co2S* instead of CuS + Co2S83. 
b. Siegenite (Nickel-linnetie) from Mineral Hill, Ma. 
_ A mineral, which has sometimes been confounded with Car- 
rollite, occurs at the Mineral Hill Mine, Carroll County, Md, 
about eight miles from Finksburg. 
__Itis found in a vein in chlorite slate and is associated with 
chalcopyrite, erubescite, blende, pyrites, magnetite, actinolite 
f and quartz. It isso intimately mixed with chalcopyrite that I 
found it impossible to pick out enough of pure material for a 
single analysis, though I had used several pounds of the mineral. 
The only impurity, as can be seen by examining it with a mag- 
nifier, being chalcopyrite, it is easy to correct the analyses by 
deducting it from the same. : 
The color is pale steel-grey, with a distinct yellowish hue, un- 
doubtedly owing to an admixture of chalcopyrite; its cleavage 
Is distinctly cubical. . : 
_ Dissolves slowly in nitric acid, but more readily than Carrol- 
lite, without separation of sulphur. 
The following results were obtained by the analyses of two 
different specimens: = 
Sulphur, - - - 39°70* 4115 p.¢. 
opper, wes - +993 363“ 
Iron, : : 1-96 20." . 
Nickel, de ar - 29°56 i « (from 3.) 
Cobalt, — - : : 25°69 BOG: Lee em, 
Insoluble, —- - - 045 126 * 
S 99°59 100 00 : 
The nickel and cobalt in analysis IJ. were in about the same 
Proportion as in I. 
th the copper and iron result from the presence of 
er require 
alcopyrite, 
therefore contained 642 p. c.; 
3°20 p. c. of iron and 
nite analyzed con- 
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Motte, Missouri. 
has been used for a 
# Some was accidently lost. 
