101 
TALC. 
Talc is a very soft mineral consisting of acid metasilicate 
of magnesium (H 2 Mgs Si 4 0i 2 or otherwise expressed, H 2 0-3Mg0- 
4Si0 2 ). In colour it varies from white to greyish green, usually 
being pale apple green. This mineral is characterized by its 
softness and unctuousness. It occurs generally in foliated 
masses with a pearly lustre, sometimes granular or fibrous. 
The massive granular or crypto-crystalline variety is known 
as steatite, while the fibrous variety is called agalite. 
Soapstone is a rock consisting very largely of talc and gets 
Us name from its soapy feeling. It is also called potstone. 
In additon to the foregoing, the following names are ap 
plied to talc, by the trade: asbestine, French chalk, mineral pulp, 
talclay, and verdolite. 
USES. 
The particular properties of talc which makes it useful in 
the industries are its softness, slipperiness, refractoriness, non 
conductivity of heat and electricity, and its resistance to the 
a ction of most chemicals. 
The principal use of talc in this country is in the making 
Paper. For this purpose it should be very finely ground, free 
r ° m grit, and as nearly white as possible for the better grades 
°f book paper. It is used as a filler to be added to the pulp 
to Produce a white, opaque paper and also in the coating of 
Paper. Agalite, on account of its fibrous nature, is the variety 
m °st desired by the paper trade because of its greater "retention” 
an d the somewhat stronger paper resulting from its use. 
Powdered talc is used in large quantities in the manufacture 
a fi ta ^ Cum P ow der and other toilet preparations, and also as 
Uer or loader in the cheaper grades of toilet soap. For 
, . Powders a very pure grade is employed. It should be 
1 e and very free from grit. For soap the colour is not so 
Portant a matter, but freedom from grit is insisted upon. 
^ or filling and dressing cotton cloth white, grit-free powdered 
£ 0r C 1 . S !ar S e, y used. It is also used in the preparation of cloth 
„ Wm dow blinds, and to a lesser extent for other textile purposes.