MINERALOGY OF BLACK LAKE AREA. 
63 
ZIRCON. 
A few scattered crystals of zircon were observed on specimens, from 
the old Standard mine, of the new mineral, colerainite, which is described 
on page 66. 
The crystals, measuring 2 mm. in length by 1 mm. in width, have a 
reddish-brown colour, and a brilliant lustre; they are simple combinations 
of the second order prism, a(100), with the first order pyramid, p(lll), 
and in most cases they are doubly terminated. 
EPIDOTE. 
Epidote occurs only as a secondary rock constituent, being especially 
abundant in some of the diabase masses. 
TOURMALINE. 
A few specimens bearing crystals of tourmaline were collected from 
the dump at the old Standard mine. These specimens doubtless came 
from a pegmatite dyke, and they consist mainly of plagioclase, optically 
near albite, with a little muscovite. The flakes of muscovite measure 
up to one cm. in diameter and are much contorted ; microscopic crystals 
of reddish-brown garnet are also present, especially in the vicinity of the 
mica. 
The tourmaline has a greenish-black colour, and the largest crystal 
observed measures 4 mm. in width, by 1*5 cm. in length. The crystals 
were not measured on the goniometer but by inspection they are seen 
to be trigonal prisms, heavily striated along their length, terminated by 
the rhombohedron. 
HYDROUS SILICATES. 
SCOLECITE. 
Scolecite was reported from this area as long ago as 1890, in which 
year the Annual Report of the Geological Survey 1 refers to a specimen 
from “Black Lake, township of Coleraine" as having been presented to 
the mineral collection by Dr. J. T. Donald. The following description of 
these specimens is given by Robert H. Jones 2 : “In one of the granulitic 
dykes on the Glasgow and Montreal Company’s property, Professor 
Donald found and sent to me a sample of scolecite, which occurs in 
transparent glassy needles, filling minute veins, and in masses of white, 
grey, and colourless radiating fibres." 
A specimen collected in 1913 by Robert Harvie from the Glasgow 
pit of the British American Asbestos, now the Asbestos Corporation, 
was identified by one of the writers as scolecite. The mineral occurs 
* Geol. Surv., Can., Ann. Rept., voL V, pt. 1, 1890-1, p. 68A. 
* Jones, Robt. H., “A»bestoa and aabestic, their properties, occurrence, and uses,” published by 
Crosby Lockwood and Son, London, 1897, p, 150, 
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