ae f ‘. 
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234 Mineralogical Notices. 
colored powder. This was heated to redness in a silver crucible 
with caustic potash ; prior to red heat combination took place with 
some violence, and on boiling with water a grey flocculent precip- 
itate went rather rapidly to the lower part of the filter, which was 
washed with a little boiling’ water. This precipitate on drying 
changed to a dark-grey color. Before the blowpipe with borax, 
in the reducing flame, this gave a clear globule, yellow while hot, 
fine green while cold, producing these changes as often as desired. 
A small portion boiled in nitric acid, dried and exposed to the 
blowpipe alone on the platina wire, fused into brick-red globules, 
but on urging the reduction flame, after a little time these globules 
fused together with a brilliant light and left a grey porous mass. 
These actions before the blowpipe are characteristic of vanadium. 
If only a minute quantity of the grey powder is used, the bead is 
yellow while hot, but the green color is scarcely visible. 
After separating the grey powder, hydrochloric acid was added 
to the filtered liquor in excess. Evaporated to dryness, silica was 
separated ; but previous to drying there appeared a small quan- 
tity of grey powder, which, after twenty-four hours’ exposure in 
water to the air, changed to a distinct green color. This is prob- 
ably the silicate of vanadic oxyd, and it passed in solution through 
the filter; it is almost impossible to separate it from the silica, 
which was again fused for a considerable time with the caustic 
potash and separated by hydrochloric acid. The silica was now 
mixed with a number of colored grains, which, under the micro- 
scope, varied from a transparent red to a dark black, and were 
probably VO? and VO*, combined with the silica. From the 
washing a small portion of alumina was afterwards separated by 
ammonia. From the absence of all metals except iron and the 
minute quantity of copper before mentioned, it is probable that the 
mineral here is in the state of vanadic oxyd VO2. I regret that 
my stock of this interesting mineral is so nearly exhausted as to 
preclude any farther investigation, but as it must exist there 1n 
abundance, and the vanadic oxyd seems to me to amount to at 
deast 20 per cent., I trust we shall not be long without more 
knowledge on this subject. On igniting the vanadiate of ammo- 
nia from the first mineral in a platina capsule, a combination with 
the platina took place, forming a dark bluish-black stain which 
Id only be removed by scraping; this made me cautious In 
using platina vessels. The combination with silica would prob- 
ably render the process in question useless for quantitative analysis. 
ee 
