60 
MICA SCHIST. 
Mica Schist is a rock composed largely of mica and quartz. 
The mica occurs in small scales all similarly oriented, thus 
giving the rock its typical structure, which is known as schistose. 
This foliation or schistose structure permits of easy cleavage 
along the planes parallel to the mica scales, while the rock is 
difficult to break in other directions. 
The particular variety of this rock which is found to be 
best suited to the purpose described below is that in which 
sericite is the mica present. This variety is more definitely 
designated as sericite schist. 
A sample of sericite schist furnished to the writer by a 
foundryman was tested by Dr. H. T. Kalmus at the School 
of Mining, Kingston, and its melting point determined to be 
1629°C., or about 100° lower than that of pure kaolin. 
Its composition is as follows 1 :— 
SiC>2 
88-00% 
AI2O3 
5-43% 
FeO 
•50% 
FejOs 
3-29% 
CaO 
•33% 
MgO 
•40% 
T1O2 
•39% 
K 2 0 
1-30% 
Na 2 0 
•22% 
H 2 0 (Combined) 
•88% 
100-74 
USES. 
An increasing number of foundrymen are substituting 
mica schist for the firebrick used for lining cupolas. The rock 
is broken into convenient size and shape, about six or eight 
inches long, four or five inches wide and a couple of inches thick, 
and cemented into place with fireclay and fragments of the rock 
Analysis by Mr. H. A. Leverin, Mines Branch.