On the Chemical Constitution of Warwickite. 353 
new species under the name of Einceladite.* As however the 
. limestone in which it occurs, often contains altered and hydrated 
sles cases 
minerals, such as the well known steatitic spinels and pyroxeues, 
1 suggested that it was itself not improbably an altered mineral, 
a conjecture which derived additional support from the fact that 
a spinel in contact with one of the crystals of Enceladite, was 
in part converted into a soft substance resembling serpentine. 
determined therefore to examine the small hard and brilliant 
erystals of Warwickite which in form and cleavage so much re- 
semble the Enceladite. 
The specimen containing them was from the original locality 
in the vicinity of Edenville, Orange county, New York, an 
consisted of a white crystalline limestone enclosing small bril- 
liant octahedrons of translucent greenish spinel, and crystalline 
grains of brownish or greenish yellow chondrodite, with occa- 
sional grains of serpentine. ‘Ihe crystals of Warwickite, which 
penetrate in every direction the cleavable calcareous spar, are very 
small, the largest being scarcely half a line in diameter, and not 
more than three or four in length. Their characters correspond 
perfectly with the description of Shepard; they are oblique rhom- 
ic prisms, but rounded both on their lateral and terminal edges, 
so that it is impossible to measure them ; the macrodiagonal cleav- 
age is perfect and exhibits in a high degree that metallic lustre 
cmmmopper-red reflection which formerly obtained for the mineral 
the 
name of hypersthene. The exterior of the crystals is brown- 
sh black with a vitreous lustre; the surface is broken by mark- 
ings or rifts, oblique to the prism and apparently corresponding to 
the obliqne cross cleavage, observed upon the lateral cleavage 
anes. The surface of the crystals has a hardness of 6, (Shep- 
ard,) while that of the cleavage planes is somewhat less. When 
_. €xposed to the weather, the mineral becomes soft, pulverulent 
and of an ochre-yellow, still however retaining the characteristic 
cleavage. 
By the action of dilute hydrochloric acid, which does not act 
Upon the crystals, a portion of them were freed from their gangue, 
and they were afterwards carefully picked out from the foreign . 
Minerals. The whole weight of the crystals which I was thus 
able to command was but about five decigrammes. They were 
first employed for a determination of the specific gravity, and 
after having been carefully boiled in water, to expel any airbub- 
bles, gave the number 2°89. Sage 
The mineral was finely pulverized and the powder dried over 
sulphuric acid at the ordinary temperature; its color was dark 
purplish brown, exhibiting until the mineral was very finely di- 
Vided, the coppery reflection of the cleavage surfaces. 
oe “# This Journal, 2nd Series, vol. ii, p. 81... 
Szconp Sznms, Vol. XI, No. 83—May, 1851. 45 
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