246 The American Geologist. October, 1001. 
I. la. II. Ila. III. IV. V. 
Cu 25.63 28.95 25 15 28.00 H4..5 15 8 27.54 
Fe 34.51 38.97 35.79 39.86 30.5 39.4 38.80 
S 28.40 32.08 28.85 32.14 35.0 29.0 30.07 
SiOo 8.62 9.20 9.2 3.45 
Total 97.16 100.00 98.99 100.00 100.0 93.4 ^9.86 
I. Chalcopyrite from Allen-O'Harra calciner of the Bwtte & Bostcn 
smelter, Butte. Montana. No zinc nor nickel. A. N. Wincliell, 
analyst, 
la. Same recalculated, omitting SiOo. 
II. Calcopyrite from Allen-O'Harra calciner of tlie Butte & Boston 
smelter, Butte, Montana. No zinc nor nickel. A. N. Wincliell, 
analyst, 
lla. Same recalculated, omitting SiOo. 
III. Theoretical composition of chalcopyrite. 
IV. Chalcopyrite from AllenO'Hara calciner, Butte & Boston smelter, 
Butte, Montana. 10 oz. Ag. Mr. Steele, assayer for the Co., 
analyst. 
V. Chalcopyrite from Castellina Maret., Italy. C. Bechi, analyst. 
Amer.Joiir. Sc, 1852, xiv, p. 61. 
The similarity between the analyses of the artificial chal- 
copyrite and the natural mineral analyzed by Bechi is strik- 
ing. It is to be noted, further, that the crystals analyzed by 
Plattner contained a slight excess of iron, as does the mineral 
here described. 
The bornite does not occur in sttfficient amount to permit 
of analysis, but its identity is established by the presence of 
the irridescent colors peculiar to it. The blue and red colors 
on different faces are abundant ; and these colors are also mod- 
ified by the yellow of the chalcopyrite. 
Both the chalcopyrite and the bornite have been formed by 
sublimation, and not by fusion, since the temperature of the 
furnace never rises high enough to fuse the ores present. 
Summarizing, we have here another example of chalco- 
pyrite as a ftu"nace product ; in this case it is formed by sub- 
limation ; and, as it forms, it replaces and destroys the iron 
rails of the calciner. Further, we have the formation of born- 
ite in small amounts by sublimation tuider the same condi- 
tions which lead to the formation of chalcopyrite in much 
larger amounts. 
