30 
CONTRIBUTIONS TO MINERALOGY. 
[BULL. 262. 
IV. COMPOSITION OF VANADIFEROUS SILICATE IN CARNOTITE 
ORE. 
As already mentioned, the ores contain a vanadiferous silicate free 
from uranium. To the end of ascertaining its composition, if possible, 
ore No. Ill (p. 25), from the Yellow Bird claim, low in carnotite, but 
relatively rich in vanadium, was treated as follows: 
The carnotite from 10 grams was extracted by cold, dilute nitric acid, 
and the well-washed residue, consisting of coarse sand and an utterly 
amorphous mud, by 4 per cent sodium carbonate solution to get rid of 
the small amount of silica presumably set free, but not dissolved by the 
acid. This amounted to 0.35 per cent in duplicate determinations, and 
together with 0.06 per cent in the acid solution, or 0.41 per cent in all, 
may serve as a maximum figure by which to gage the action of the 
cold acid on the silicate or silicates in the ore. The residue was then 
digested for several hours with warm nitric acid of about 1.2 specific 
gravity until, as shown by a companion test, its action had ceased. It 
was then filtered, washed, and digested with 5 per cent sodium car- 
bonate solution to dissolve the copious deposit of silica. The final 
residue was collected in a Gooch crucible, washed with sodium carf 
bonate, followed by dilute nitric acid to remove all alkali, then by 
alcohol to prevent turbidity in the filtrate, and dried by suction of the* 
pump. In it the water was determined at different temperatures; alsc 
its general composition. a From the sodium carbonate filtrate tH 
silica was obtained by two evaporations and nitrations; also the trifling, 
amount held by the acid solution. This latter was then fully analyzec 
and the complete results follow: 
Si0 2 
A1 2 3 
VA 
Fe 2 3 
CaO 
MgO 
K 2 
Na 2 
H 2 Oatl05 o C.-.: 
H 2 Oat300°C.... 
H 2 above 300° C 
Per cent in 
ore. 
6.48 
& 2. 445 
c.965 
d . 875 
.035 
^.654 
.546 
.03 
/1.66 
/ . 44 
/.62 
14.75 
Per cent cal- 
culated to 
100. 
43.94 
16.58 
6.54 
5.93 
.24 
4.43 
3.70 
.20 
11.26 
2.98 
4.20 
100.00 
Ratios. 
0. 727! 
0. 1622J 
.04341 .242: 
. 0370 J 
. 0043^ 
. 1099/ ' 114 
. 0393 1 
0037/ 
.043 
.922 
.165 
.233 
«SiOo, 48.89; AloO { , Fe 2 3 , zircon, etc., 0.44; TiC, 0.08, MgO, 0.01; KoO, 0.11: Na.,0, 0.03; H,,0, 0.0 
total, 49.63. & 2.45 and 2.44. c 0.93 and 1.00. ''0.87 and 0.88. e 0.652 and 0.657. /Determine 
on a separate portion of the same powdered sample. Sec p. 25, footnote, for data. 
Also traces of titanium, manganese, and lithium. 
