MINERALOGY OF BLACK LAKE AREA. 
57 
Calcite, aragonite, clinochlore, and porcellophite are the minerals 
most commonly associated with the emerald-green crystals; the yellow 
variety has in addition andradite associated with it. 
Southwark Pit. Clove-brown and reddish-brown crystals are associ- 
ated with the colourless grossular garnet described on page 46; the largest 
crystals observed have a length of 1*5 cm., and measure 4 mm, across 
the prism. Several crystals were measured and on these the forms 
tabulated on page 58 were noted; the habit is usually determined by 
the forms a(010) and s(311); p(lll) is sometimes fairly large and the 
base is absent. 
Caribou Chrome Pit. This locality yields reddish-brown crystals of 
habit similar to the last. 
American Chrome Pit. Vesuvianite occurs here in compact masses 
of pale yellow colour; where more coarsely crystallized, it forms a network 
of prisms, but well terminated crystals were not seen. 
Union Pit. Bottle-green, as well as reddish-brown, vesuvianite occurs 
at the Union pit, but in neither case was it found to be well crystallized ; 
the former is usually associated with clinochlore and brownish diopside, 
the latter with colourless, rose, and pale green grossularite. 
Hall Chrome Pit. At this pit there is found a massive vesuvianite 
rock, almost uncoloured, associated with which are crystals having an 
emerald-green colour. 
Table of Occurrences. For convenience of reference, the differently 
coloured varieties of vesuvianite occurring in the area at the principal 
localities visited are tabulated below: 
Pit 
Emerald- 
green 
Lilac to 
colourless 
Pale 
yellow 
Reddish- 
brown 
Bottle- 
green 
Mnntrpsil rhmmi* . . ... 
X 
X 
X 
X 
X 
X 
X 
X 
Southwark. 
Uarihan 
American 
X 
Union. . 
Hail 
X 
Crystallography. 
About sixty of the crystals were measured, these being chiefly of the 
lilac, emerald-green, and pale yellow coloured varieties, which, owing 
to the brilliance of their faces, present almost perfect material for gonio- 
metric work. The total number of forms observed in this series of crystals 
