Roger W. Cramer on sat 24 jan 04
The website below gives an excellent chemical analysis of pyrophyllite and
expecially its relationship to talc. Its a question worthy of John H. and
Ron R. why we do not see this chemical more frequently in glaze and clay
formulas. Roger
http://mineral.galleries.com/minerals/silicate/pyrophyl/pyrophyl.htm
logan johnson on mon 26 jan 04
Hey Roger,
Thanks for posting the wonderful web site!!! Is there such a thing as "too many bookmarks??? "Say it aint so!!"
"Roger W. Cramer" wrote:
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John Britt on mon 26 jan 04
Roger,
Pyrophyllite is an aluminum silicate while talc is a magnesium silicate.
The web link you listed indicates physical similarities not necessarily
chemical similarity. Pyrophyllite is more similar to Kyanite or mullite
and is usually used in claybodies to decrease thermal expansion and
contraction. (Calcining kyanite decomposes it to mullite and silica.)
Hope that helps,
John Britt
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