24 
MUSEUM BULLETIN NO. 27. 
Occurrences. 
Montreal Chrome Pit. The best crystals were found at the Montreal 
chrome pit, especially in vugs in the massive lilac vesuvianite rock, or 
coating the slickensided surfaces of certain fissures in the serpentine. 
Three different habits were noted: one of these shows the simple acute 
negative rhombohedron f(0221), like the common form of <s Fontainebleau 
sandstone a second habit is also a simple negative rhombohedron, the 
so-called “cuboid” $(0554), and crystals of this type might easily be 
mistaken for chabazite. In each case these usually occur as interpenetra- 
tion twins, with twin p!ane_c(0001). The third habit is prismatic, the 
forms exhibited being m(1010), the_positive rhombohedra r(1011) and 
M(4041) and the scalenohedron r(35 84) ; M is larger than r while P(3584), 
although appearing as very bright facets on all the crystals measured, is 
almost microscopic in size. 
The rhombohedral crystals are seldom more than 1 mm. in 
diameter; the prisms are similarly thin needles with a length up to 
2 cm. 
The massive calcite occurring at this pit is occasionally mangani- 
ferous, forming transparent or translucent cleavable masses of lilac 
colour. 
Caribou Pit. Crystals of calcite are found within the druses of a 
miarolitic granite of aplitic character at this pit; the calcite, in simple 
negative rhombohedra f (0221), rests upon crystals of white albite which 
forms the walls of the druses. 
American Chrome Pit. The grossular garnet described below (p. 48) 
as exhibiting the very rare cube faces, is associated with massive white 
calcite, 
DOLOMITE. 
Although carbonates of lime and magnesia are abundantly associated 
with serpentine in many regions where the latter rock is found, in the 
serpentine belt of Quebec they are seldom met with, and then only in 
small amount. Dolomite may occasionally be seen as very narrow 
veinlets following joint planes which traverse the massive serpentine. 
Poorly crystallized specimens were collected from the Black Lake 
Consolidated Company’s chrome prospect on the east side of Kings 
mountain. The crystals are very flat rhombohedra, with a somewhat 
lenticular form and a rough drusy surface. 
SIDERITE. 
Only one occurrence of siderite was observed. Brown rhombohedra, 
with a diameter of about half a centimetre, are associated with the 
apatite crystals described on page 81. 
