Martie (AKA the Kiln Priestess) on mon 25 apr 05
John:
I have come across some interesting information about the hardness or strength
factor between porcelain and earthenware from an old English book entitled, "Pottery
and Porcelain: A Guide to Collectors," by Frederick Litchfield, 1880.
"Paste: The word signifies the body or matter of the potter's production, as
distinguished from its decoration. The paste of pottery is hard or soft according to its
composition--thus a brick is soft; a piece of Queen's ware, or any stoneware, is hard. In
porcelain hard paste the product is a mixture of china clay (kaolin) and felspar
(petuntse), and breaks with smooth vitreous fracture in which point it differs from
pottery. Soft paste porcelain is the result of a mixture of fine clay with silex and other
materials."
It seems that part of the distinction in the hardness and durability of different ceramic
products is noted by how a ceramic body breaks or cleaves in addition to the
ingredients that go into the body.
Martie
| |
|
