30 
MUSEUM BULLETIN NO. 27, 
although a very large number were examined. Determinations of the 
refractive index, by the immersion method, were not altogether satisfac- 
tory, but indicated a value between 1 • 545 and 1 • 554. 
The powdered material effervesces when treated with dilute hydro- 
chloric acid, and the stichtite appears to be easily and completely 
soluble, yielding a bright green solution; an insoluble residue, however, 
always remains, which is white and no doubt consists of the pale coloured 
serpentine with which the stichtite is intimately associated. The fil- 
tered solution reacts for chromium and magnesium. Heated before the 
blowpipe, the mineral loses its colour and turns brownish or greenish- 
white, but it does not fuse nor become magnetic. The feebly magnetic 
character after heating referred to by Petterd is doubtless to be ascribed 
to admixed chromite in the Tasmanian specimens. At the old Megantic 
mine also, the adjacent serpentine includes a few small scattered grains 
of chromite, and it is no doubt from such grains as these that the chro- 
mium of the stichtite has been derived. 
On most of the specimens collected there is a little magnesite or 
dolomite, in very minute white crystals, associated with the stichtite, 
especially where the latter occurs as narrow veinlets. In view of this 
it may be pointed out that the subtraction of one molecule of MgCO* 
from Hezner’s formula would bring it into almost exact correspondence 
with that earlier assigned to the mineral by Petterd ; but the descriptions 
do not refer to the presence of magnesite on the Tasmanian stichtite 
specimens. 
Silicates. 
ANHYDROUS SILICATES. 
FELDSPAR, 
The various feldspars have already been referred to in the section 
dealing with the rocks of the serpentine belt. 
The crystals of albite, mentioned above as occurring with calcite 
at the Caribou pit, are small prismatic individuals 2 mm. in length 
exhibiting twinning on b(010). They are not terminated and are of 
no special interest. 
ENSTATITE AND HYPERSTHENE. 
These minerals occur as essential constituents of peridotite and 
pyroxenite, and have been referred to under the descriptions of these 
rocks. 
DIOPSIDE. 
While diopside occurs at several localities in the area only that from 
the Montreal chrome pit has been studied in detail. 
