Page 10 - VRT PORCELAIN
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hard-paste soft-paste Bone china
sometimes "true porcelain", is It is weaker than "true" hard- Composed of bone ash,
a ceramic material that was paste porcelain, and does not feldspathic material, and kaolin.
originally made from a require either the high firing It has been defined as "ware
compound of the feldspathic temperatures with a translucent body"
rock petuntse and containing a minimum of 30%
kaolin fired at very high The material originated in the of phosphate derived from
temperature attempts by many potters to animal bone and calculated
replicate hard-paste calcium phosphate.
fired at extremely high
temperatures (2550° F) mixing white clay with 'frit' the strongest of the
approaching the melting point (a glassy substance that was porcelain or china ceramics,
of iron at 2700° F. a mixture of white sand, having very high mechanical
gypsum, soda, salt, alum and and physical strength and chip
a compact and fused body, nitre.) resistance, and is known for
and its fracture is brittle, its high levels of whiteness and
homogenous, and smooth. translucency.
