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Sierralite Talc

Alternate Names: Sierralite 252HS

Description: Chlorite

Oxide Analysis Formula
SiO2 32.00% 0.63
MgO 34.00% 1.00
Al2O3 21.00% 0.24
CaO 0.04% -
Fe2O3 0.23% -
LOI 12.60%n/a
Oxide Weight 103.35
Formula Weight 118.25


This is 95% chlorite, less than 5% talc, less than 1% quartz. High alumina content (21%) and low iron oxide content. Useful in ceramics and refractory materials requiring low thermal expansion and good thermal shock resistance. They claim it "disperses easily in waterborne coatings and produces a low viscosity in solvent-borne coatings".

This could be a viable substitute for C-98 Texas talc from a physical properties standpoint. However it targets a market that can tolerate much higher costs, so the its very high price could disqualify it for you.

Related Information


Materials Talc
A source of MgO for ceramic glazes, a flux or thermal expansion additive in clay bodies, also used in the manufacture of cordierite.
Materials Silverline 303 Talc
Materials Steatite
Materials Natural Talc C-98
Typecodes Flux Source
Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
Hazards Talc Hazards Overview
Talc is invaluable in the ceramics industry, it is used as a glaze and body ingredient and as a parting a release agent in various processes. Is it safe?
Sierralite 252hs Talc information
URLs 252HS.pdf
Sierralite 252hs Talc data sheet


GE Brightness 92
Density (Specific Gravity) 2.64
pH for dry powder 8.5
% Passing 200 Mesh Wet 99.8%
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