338 W. F. Fontaine—Minerals in Amelia County, Va. 
Philad., June 24, 1882. Professor Dunnington has analyzed this 
monazite also. For his results, see Am. Chem. Jour., vol. iv, 
p- 188. The most noteworthy feature of this analysis is the 
considerable amount of thorina found.* 
Helvite-—This mineral occurs very rarely, and is found only 
in pit No. 2. It seems to occur only in the walls of the cavity 
in this pit, and is deposited in the interstices of the light pink 
spessartite mentioned above, which is itself found in the open- 
ings between the albite crystals that formed on the walls of 
the open space. The helvite seems to have been the last min- 
eral to be deposited in the vein, and its constant association 
with such a highly manganiferous garnet, is an interesting fea- 
ture. It seems to have been deposited in the form of erystal- 
line granular particles, that rarely show crystal faces or forms. 
good deal of it is now ina pulverulent condition that may 
result from partial alteration. This mineral has been carefully 
examined in the laboratory of the University of Virginia by 
Mr. B. E. Sloan, pure material being taken. I extract the 
results of this examination from the “Notes of Work of Stu- 
salad ete., etc., published originally in the London Chemical 
ews. 
‘Color, wax- to lemon-yellow ; streak, very pale lemon-yel- 
low; luster, vitreous; translucent; hardness =6; sp. gl = 
3°25. Fusible before the blowpipe flame with intumescence. 
Decomposed by hydrochloric acid with the formation of gelati- 
nous silicic acid, and the liberation of sulphuretted hydrogen. 
Analysis gave— 
a 31°42 
Perce dc ugk setts elec see 10°97 
BeOS __.. 40°56 
MO ee ee ee 2°99 
BIO Oe 0°36 
My et ee 
from partial alteration, as it is quite intense on some particles. 
ness=6°5. Sp. gr.=6°82. In composition it is a tantalate, 
S, L. Penfield, in his analyses published in this Journal in October, oa 
wi — 
* Mr. 
(xxiv, 250), concludes that the thorina present is from mixture with thorite. 
