'Bisque' of 'biscuit' earthenware is simply the once-fired body without the addition of glaze. Green ware is unfired pottery, ready to be bisque fired.
Terracotta: Unglazed porous earthenware, mostly red.
Slip (liquefied clay) is used in casting and to decorate earthenware.
Carving: Like woodcarving removing areas of clay in the raw model, to create a raised design. After carving the object is baked and then glazed.
Plaster: Used to make moulds but was also used (especially in France) to create figurines and piggy banks. The process is the same as clay slip in moulds. There is no baking process, the plaster dries in the air and is painted after drying.
Stoneware: It became known in northern Europe after the Renaissance. Probably the majority of current glazed stoneware are salt glazed (part of the baking process).
Siderolith: White or colored volcanic clay, baked as stoneware. But Siderolith does not form a glass layer on top as stoneware does. It is finished with copper varnish. Production between 1880 and 1930. Much wanted by collectors!
Glaze: A thin coating of glass. An impervious silicate coating, which develops in clay ware by the fusion under heat of inorganic materials. Applied to porcelain or pottery body to make it waterproof and enhance colour. Glazes may be clear, opaque or coloured to various degrees.
Lead Glaze: transparent glassy glaze using lead oxide, colour green. Due to EC regulations forbidden for household use, because it is poisonous.
Tin-based glaze is white, glossy and opaque, normally applied to red or buff earthenware. The opacity and whiteness of tin glaze make it valued by the ability to decorate it with colour.
- Lustre: A type of decoration originally developed in Persia that leaves a thin layer of metal on the decorated portions of pottery.