ilLLEBBAND.] 
TELLURIUM MINERALS FROM COLORADO. 
57 
1. TETRAD YMITE. 
Specimens received in the Survey laboratory from Mr. IT. B. Trader 
md said to come from some locality near Whitehoru, Fremont County, 
proved to be tetradymite. They showed the mineral in masses of 
considerable size, which, although manifesting the eminent cleavage 
Sf tetradymite, were devoid of distinct evidences of crystal form. 
Hie specific gravity at 20° C. was 7.816. Analysis afforded the fol- 
lowing results: 
i. 
2. 
3. 
Mean. 
Atomic ratio. 
Bi. 
52.00 52.30 
46.62 1 
) 46.82 
a. 20 J 
.13 .14 
52. 13 
52.14 
0.2498 =2.0 
re 
1 46. 62 
.36511 
*5e 
1 .20 
.14 
.22 
.15 
.0025 [=2. 98 
3 
. 0044 J 
Fe 2 O s 
.22 
insoluble . . 
.15 
99.47 
1 
! 
« Appro? 
.iruate. 
