Joseph Herbert on mon 15 sep 97
I would like to add a little to the observations of Karl Platt on Albany
Slip. The quarry where albany slip was "mined out" was closed so a shopping
mall or parking lot could be built. I don t know if the previous land use
was better or worse than the current land use. The material itself was some
glacial deposit, common in New York and other parts of the U.S., that was
refined in three successive operations in different places (!) before being
sold. The process was probably more important in determining the result than
the starting material. It is difficult for me to believe that a particular
spot in Albany, New York is the only one where the glacier left stuff of a
special kind. What is true is that no one has found a deposit and processing
scheme to replace what is lost. There is some possibility that you could
find a similar material just by sampling various till banks, ground moraines,
or kettle deposits, then dividing the sample material by grain size using
screening and settling methods, and then test firing each fraction. Quite
possibly some fraction, probably all the material below X size, would act
like Albany slip. Don t know, but it could be. Lots of Iron bearing clays
melt rather nicely. Glacial material contains a lot of clay, rock fragments,
and finely ground feldspar - pretty much the requirements for a high fired
glaze. It could happen.
Joseph Herbert
JJHerb@aol.com
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