6'2 
contributions to chemistry and mineralogy, [bull.167. 
If hessite and native tellurium constitute the foreign admixture the 
ruineralogical composition of a and c is shown to be as follows: 
. 
• 
Nile- 
84.44 
13. 51 
2. 05 
97. 89 
1.38 
... 
. fa 
Hfwita 
Tellurium 
100. 00 
100.00 
There is here indicated a considerable selective separation of the 
foreign minerals, since the relative proportions of tellurium and hessite 
arc very different in the two mixtures, but the amounts operated on 
were so small that a very slight actual error in a determination might 
give rise to this change in the relative proportions of impurities with- 
out affecting materially the ratios found for the components of the 
nickel telluride. The three analyses taken together point unmistak- 
ably to XiTe. as the formula for the latter mineral. The question then 
arises. Is this Genth's melonite. or is it a new mineral? Genth found: 
Te 73. 43 
Ni 20. 98 
Ag 4.08 
Pb 72 
99. 21 
from which, after deducting hessite. altaite. and free tellurium, he 
deduces the formula Ni 8 Te 3 , requiring Te 70.49 and Xi 23 51. 
The difference between his and my own analyses is too great to 
admit of bringing them into accordance, yet I am indisposed to believe 
that two minerals are represented, for both occurrence and appearance 
are opposed to such a view. The present mineral is from the same 
source as Genth's. Its physical characteristics, so far as ascertainable, 
coincide with those of melonite. and it is called melonite by the people 
at the mine, vlelonite was considered by Genth to be hexagonal on 
the strength of its eminent cleavage and the observation of a single 
microscopic 0-sided plate. Mineralogically a hexagonal form in the 
pyrite group, assuming this mineral to belong there, is not to be looked 
for, but the evidence in favor of hexagonal crystallization is too mea- 
ger to permit this to be used as an argument one way or another. 
CoLORADornsf. 
One small specimen from the Norwegian mine showed in dolomite, 
petzite. hessite. and a mercury telluride. Superficially the latter was 
not to be distinguished from the accompanying petzite and hessite. and 
it was in msurheient amount to admit of analysis for the determination 
