CERAMIC TERMS & DEFINITIONS
Bisque (or Bisquit): clayware that has been fired once for hardening, but has not yet been glazed.
Bisque fire: the first firing, or baking, in clayware manufacture, which hardens the ware into its final shape.
Blank: an undecorated piece of dinnerware or glassware, usually one that will be subjected to further processing for decorating.
Body: the physical composition of a piece of clayware as opposed to its glaze or decoration.
Bone China: china that contains a varied percentage of animal bone ash, mostly ox bone, which is burned and ground to a fine powder for added strength, translucency and whiteness. Developed originally in England, but now made in many other countries as well.
Bright gold: a liquid gold paint decoration which, when fired, comes out bright and therefore requires no burnishing or polishing.
Casting: a process in which liquid clay, or slip, is poured into a mold and then allowed to set. The result is a piece of clayware duplicating the shape of the mold.
Casual china: a non-porous type of clayware made of special white clay and fired at exceptionally high temperatures. The finer grades are generally thin, translucent, resistant to chipping, and ring clearly when struck. The word should not be used as a generic term for all dinnerware.
Ceramics: a generic term referring to articles made of so-called earth materials (clay, sand, etc.) processed by firing or baking. The classification includes pottery, earthenware, porcelain, china, fine china and bone china.
Clay: The essential raw material for ceramic formed when rock breaks down either due to the weather or through chemical processes as in the clay used for dinnerware.
Coup shape: a contemporary plate shape lacking a shoulder, like an inverted Frisbee, flat across the diameter and rolled up slightly at the rim.
Crackled ware: clayware whose surface is marked by a network of tiny cracks deliberately induced for decorative effect by sudden cooling.
Crazing: a defect in clayware glaze consisting of a network of tiny cracks caused by the difference in the rate of contraction between body and glaze. It is almost the same in appearance as deliberate cracking.
Decal: a special design-bearing sheet used in dinnerware decoration. The paper is then removed resulting in the transfer of the decoration to the ware. Subsequent firing makes it permanent.
Earthenware: a type of clayware fired at comparatively low temperatures producing a heavy porous body that is opaque, not as strong as stoneware or china, and lacking that product's resonance. Earthenware dinnerware is typically in the low and medium price brackets and lends itself to a variety of decorative styles and methods, making it well-suited for everyday use. There is some high-priced English earthenware.
Embossing: a raised or molded sculpting produced either in the mold or formed separately (seldom done), and applied before firing.
Feldspar: a common mineral used in some china and glazed materials.
Filling-in: a decoration process whereby transfer print outlines applied to a piece are filled in by hand to produce multi-colored effects.
Firing: a baking process under carefully controlled temperatures to which all ceramic ware is subjected for either hardening, strengthening, or fusing.
Fine china: thin and translucent, it is quite strong in spite of its delicacy. It is made of top quality clays fired at high temperatures that cause them to fuse into a hard, non-porous body.
Flatware: in dinnerware, any flat or near-flat piece such as a plate or platter.
Glaze: a glossy transparent or colored coating baked onto a clayware body for decorative purposes and to make it non-absorbent and more resistant to wear.
Hollow ware or hollowware: any clayware pieces, such as cups, pitchers, of bowls that have three-dimensional properties, as opposed to flatware.
Hotelware: heavy china dinnerware made specifically for use in hotels, institutions, etc. It is stronger than china for home use, but has neither the transparency nor the delicacy of the latter.
Ironstone: a much misused term that should be used only in reference to earthenware of good quality and better-that-average strength. True ironstone was originally developed in England. Originally it was a form of stoneware said to contain powdered iron slag. Ironstone has a slightly porous body.
Jiggering: jigger machine used to make mugs. A rotating system is used to form the clay into the shape of the mold.
Kiln: the oven in which ceramic ware is fired or baked.
Banding (or Lining): a dinnerware decoration, either machine-or-hand applied, consisting of one or several parallel lines running around the outer edge of a plate.
Luster: a ceramic glaze coating, metallic in nature, which gives the finished piece an iridescent effect.
Matte finish: a flat glaze finish without a gloss or reflective shine.
Melamine: chemical name of the plastic compound generally considered the leading plastic for making dinnerware.
Mould: a plaster of paris mould of the clay shape from which a clay form can be reproduced.
Open stock: an approach to dinnerware retailing in which the ware is sold in individual pieces or small groups rather than in complete, predetermined compositions or sets. Implied, also, is the fact that patterns offered in open stock will be available for an indefinite period following their introduction.
Ovenware: clayware that is able to withstand the heat of a kitchen oven without damage, thus permitting a homemaker to prepare oven-cooked food in it and then use it for table service.
Overglaze decoration: design applied to clayware after it has been glazed.
Place settings: usually five (although today four and even six are becoming common) matched pieces of dinnerware for setting a single place at a table. The pieces most commonly included are a dinner plate, salad plate, soup/cereal bowl, cup and saucer.
Porcelain: a hard, translucent clayware body that differs very slightly from china in ingredients and manufacturing process. In most respects the two are so much alike that the term may be used interchangeably. Porcelain usually consists of 50% kaolin, 25% quartz, and 25% feldspar. Kaolin provides plasticity, durability and consistency and influences the whiteness of the body. Quartz provides stability and feldspar provides vitrification.
Porosity: the ability of clay to absorb moisture.
Pottery: can be used as a generic term, much the same as "ceramic." When referring to a specific ware, pottery refers to a very durable form of clayware made of crude clay and fired at comparatively low temperatures. It lends itself best to colorful, informal decoration and simple shades.
Potter's wheel: a round platform rotated either mechanically or manually upon which the potter throws, or forms, a circular shape.
Reject: a piece of ware, which, because of an imperfection, does not meet certain quality standards and therefore is withheld from shipment.
Run of kiln: (or R.K. or R.K. selects): the entire production runs without quality control to separate second grades and rejects.
Salt glaze: a semi-matte or half-glossy glaze obtained by injecting salt into the kiln during the glaze firing.
Screenprinting: a method of ceramic and glassware decorating in which stencil-like screens are used in applying colors to the ware.
Second grade: ware that exhibits noticeable minor defects that do not affect the ware's usefulness.
Selects: near-perfect dinnerware pieces as indicated in a process of selection in which imperfect pieces are removed from the group.
Shoulder: the raised rim of the traditionally rim shaped plate.
Silica: one of the earth's most abundant minerals and a vital ingredient in ceramic manufacture. It is the basic component of glass as well as of ceramic glazes and high-quality clayware bodies.
Slip: a mixture of clay and water with a cream-like consistency. It is used both for producing ceramic body and for ceramic decoration.
Stonelite: somewhat improved earthenware, it combines the merits of both earthenware and stoneware. Bright as earthenware, it is dense and strong like stoneware. It stands up well to constant use.
Stoneware: a hard addition of grinded stone clayware made of light-colored clay and fired at high temperatures (2,400 degrees). It is non-porous and quite durable but does not have the translucence of fine china.
Terracotta: a brownish-orange earthenware commonly used for ceramic sculpture, ornament, and dinnerware. It is an Italian term meaning baked earth.
Texture glaze: a colored glaze in which dripping, eruption, or some other controlled disturbance is introduced to heighten the decorative effect.
Throwing: forming clay manually by shaping it as it is rotated on a potter's wheel, or revolving platform.
Translucence: that quality of fine china or melamine dinnerware that makes it semi-transparent. Placing the hand across the back of a piece and holding it up to the light may demonstrate it. A silhouette of the hand will be visible through the body of the piece.
Transfer printing: a decorating method similar to the one in which decal is used but permitting only one color at a time to be applied.
Tunnel kiln: a long tunnel-like oven in which clayware is fired by being carried through on flat cars that move along very slowly.
Unbreakable: literally, a dinnerware piece that will not break under any circumstances. Because such ware does not exist -- even glass, ceramic, or melamine dinnerware will break under certain conditions -- the phrase should never be used. The correct way to describe unusually strong dinnerware is "break-resistant."
Underglaze decoration: a ceramic decoration that is applied directly to the biscuit, or underglazed body, and then covered with a protective glaze coating that makes it highly resistant to wear and in which the decoration (decal) is not felt, creating a smooth surface.
Vitrified: stoneware and porcelain fired at higher temperatures, creating a stronger bond between the bisquit and outer glaze creating a more durable and harder object.