1877.] 119 [Genth, 
In exceedingly fine needles, which under the microscope appear in bun- 
dles or tufts, sometimes radiating ; some of the groups seem to have crys- 
tallized around a globule of mercury, which latter, in breaking the speci- 
men, has fallen out, leaving a round empty space in the centre of the 
crystals. Color white ; lustre silky. 
Readily soluble in very dilute nitric acid, the solution yielding a precipi- 
tate of Hg Cl by hydrochloric acid ; the mineral is also soluble in hydro- 
chloric acid, the solution contains Hg Cl, and Te Cl,, which proves that 
its composition is ‘‘ mercurous tellurate’’? = Hg, Te O,. — 
Hg,Te O, + 8H Cl = 2 Hg Cl, + Te Cl, + 4H,0 
The mineral is also blackened by ammonic hydrate. 
Name after ‘‘ Magnolia’’ District. 
7. FERROTELLURITE, A NEW MINERAL. 
A crystalline coating upon quartz, associated with native tellurium. Under 
the microscope it appears in very delicate tufts, sometimes radiating or, 
when in cavities, as very minute prismatic crystals of a color between 
straw and lemon-yellow inclining to greenish-yellow. 
Insoluble in ammonic hydrate; some of the mineral, which had been 
treated with ammonic hydrate for the purpose of removing the tellurous 
oxide present, was dissolved in hydrochloric acid. The solution contained 
tellurous oxide, ferric oxide, and a trace of niccolous oxide ; the mineral 
is therefore probably a ferrous tellurate = FeTeO,, hence the name. The 
quantity at hand is too small for a fuller investigation. 
It occurs at the Keystone Mine, Magnolia District, Colorado, associated 
with native tellurium, tellurite, and a peculiar iron sulphide, in which a 
part of the sulphur is replaced by tellurium. A preliminary examination of 
it gave Fe = 41.01, Ni= 0.72, Te = 4.06 and S = 41.73 — 87.52. The 
material for analysis was slightly oxidized, but the difference of 12.48 % 
is too great to be covered by this. I shall repeat the analysis, if ever I 
should succeed to get this mineral again. 
8. ROscOELITE. 
It will be remembered, that almost simultaneously, Prof. H. E. Roscoe 
and I investigated the mineral, which now bears his name, his paper hav- 
ing been received by Royal Society on May 10th, 1876, (Proc. Royal Soc. 
XXV, 109.) whilst mine was written and sent to the editors of the Ameri- 
can Journal of Science on May 16th, 1876. 
I regret to say that in some of the essential points our results do not 
agree. 
From the nature of the material and the information received from Dr. 
James Blake of San Francisco, no doubt can exist that, that, which he had 
sent to me, was as good and pure as it could be obtained. In my examina- 
tion (Am. Journ. of Sc. [3] XII, 32) I showed that even the apparently 
purest scales, selected with the greatest pains, were not altogether free 
from admixtures. With the greatest difficulty I obtained enough of almost 
