Biscuit porcelain is unglazed porcelain treated as a finished product, mostly for figures and sculpture.
Unlike their lower-fired counterparts, porcelain wares do not need glazing to render them impermeable to liquids and for the most part are glazed for decorative purposes and to make them resistant to dirt and staining.
Clays used for porcelain are generally of lower plasticity and are shorter than many other pottery clays.
They wet very quickly, meaning that small changes in the content of water can produce large changes in workability.
It combines well with both glazes and paint, and can be modelled very well, allowing a huge range of decorative treatments in tablewares, vessels and figurines. The European name, porcelain in English, comes from the old Italian porcellana (cowrie shell) because of its resemblance to the surface of the shell.
Properties associated with porcelain include low permeability and elasticity; considerable strength, hardness, toughness, whiteness, translucency and resonance; and a high resistance to chemical attack and thermal shock.
A more common terminology for the unfired material is "body"; for example, when buying materials a potter might order an amount of porcelain body from a vendor.
Its manufacturing process is more demanding than that for earthenware and stoneware, the two other main types of pottery, and it has usually been regarded as the most prestigious type of pottery for its delicacy, strength, and its white colour.
As these early formulations suffered from high pyroplastic deformation, or slumping in the kiln at high temperatures, they were uneconomic to produce and of low quality.