54 
MUSEUM BULLETIN NO, 27, 
colourless crystals were the only ones on which the form 0(011) was 
observed. 
Some of the druses in the deep lilac massive material are lined instead 
with crystals of a wine-yellow colour. As will appear below, analysis of the 
lilac crystals shows them to contain small percentages of both manganese 
and iron ; the association of these crystals with the yellow variety might 
be explained by assuming that, under the conditions prevailing, the most 
highly manganiferous variety crystallized out first, as indeed appears to 
have been dearly the case from an inspection of the specimens; the mother 
liquor thus became gradually impoverished in manganese, until there 
remained just sufficient of this element to counterbalance the effect of 
the iron, and colourless crystals then separated; finally the mother 
liquor having become nearly or quite free from manganese, the colouring 
property of the iron made itself felt, with the consequent formation of 
yellow crystals. It is interesting to note that the habit of the latter is 
somewhat different from that of the lilac crystals. The dominating 
forms are the prism a and the pyramid s, the other forms present, m, p, 
and t, having a relatively small development, and the basal plane is 
either absent or of trifling size. Figure 18, omitting the basal plane, 
would represent an average type. 
The minerals most frequently associated with the vesuvianite 
described above are calcite and aragonite, the latter in tufted groups 
of flat bladed crystals; less frequently there are also present diopside, 
both colourless and yellow, and a white, amorphous material, possibly 
porcellophite, a variety of serpentine. 
The emerald-green crystals are always associated with white, compact 
diopside. The latter material, as already stated on page 31, forms the 
walls and outer portions of certain dyke-like bodies which cut the serpentine 
at this locality, and it also occurs as a network of irregular veins traversing 
the massive chromite, giving to the ore a brecdated appearance. The 
vesuvianite occurs as brilliant green crystals resting on crystals of colour- 
less or pale diopside lining cavities in this compact rock; similar crystals 
are also found along fissures in the chromite, directly attached to the 
ore, but as a rule these are poorer and almost microscopic. The usual 
habit of the crystals is illustrated in Figure 20 and Figure 22. The prisms 
are square in outline, owing to the invariable predominance of a (100) 
as compared with m(110); the base, though small, is always present. 
The main pyramid in this variety is the ditetragonal form s(311), and the 
steep pyramid t(331) is also well developed. Owing to the large relative 
size of these pyramidal forms, the termination of the emerald-green 
crystals is, on the whole, more acute than in the other varieties. A 
complete list of the forms observed on these crystals is set forth in the 
table on page 58. 
