Prof. B. Silfiman, Jr., on Emerald Nickel. 
XXV.—On Emerald Nickel Texas, Lancaster 
County, Pa.; by Pet B. Sitimany, Jr. 
Saris j is the same mineral which I have before described under 
the name of “hydrate of nickel.” vere e now proposed is 
in accordance with the custom of giving a trivial name to mine- 
ralogical species, and has been suggested by my friend, Prof. C. 
U. Shepard, as peculiarly appropriate from the brilliant color and 
transparency of the mineral, resembling the emerald. The ex- 
istence of carbonic acid in this mineral as an essential constitu- 
ent, was overlooked by me from the fact that it is all expelled at 
redness, and was therefore in my analysis put down as water. 
The water given off in the close tube does not change litmus pa- 
per, and the mineral does not effervesce in dilute cold hydrochlo- 
ric acid. My attention was first directed to the probable exis- 
tence of carbonie acid in this mineral, by a notice from Dr. D. R. 
Thomson,} describing as a new mineral a carbonate of nickel 
from the United States, coating specimens of chromic iron. 
Prof. Bhepard also mentioned to.me that he had found carbonic 
acid in a a nickel mineral first described by me. I have 
therefore >a new analysis of the mineral in question, selecting 
the finest and most transparent colored specimens in my power. 
The following mineralogical description is mainly the same 
which I have before given, save that having much better speci- 
mens on which to determine the specific gravity, that now given 
may be regarded as more correct than the former determination. 
Emerald Nickel. 
Massive, stalactitic, occurring in thin crusts on chromic iron. 
Hardness = 3—3 25, being but little above cale Abe 
y = 2:570—2 698, two trials on different porti 
Pustre vitreous, brilliant. Color emerald-green. Tranepereat 
Streak delicate pea-green. Very brittle. Its pyrognostic charac- 
ters have already been so fully described in the article first quoted, 
that it is useless to repeat them here; they differ in no respect 
from those of pure artificial hydrate of nickel. 
The water of this mineral is partially expelled mak ordinary 
temperature of a water bath (212° F.); this fact led to estima- 
ting the total volatile product of the. mineral too low, in the for- 
mer description of this species. Carefully dried over sulphuric 
acid, the mineral lost on two trials 41:370 and 41-008; mean = 
AL 189 per cent. 
The carbonic acid was estimated in the apparatus described by 
Fresenius and Will for analyzing carbonates. 
eee eal 
* This Journal, ii ser., vol. iii, p. 407. t Phil. Mag., Dec., 1847, p. 541. 
x i = : £ ; 
