Ceramics, in its broadest term, defines the art of making any object from clay by baking it. Just as the term “vehicle” can mean car, airplane, or spaceship, the term “ceramics” includes a like number of variations, either in design or materials.
Basically, the chemical composition of china is a combination of clay, kaolin, feldspar, and quartz. Other materials may be added, depending on the relative quality of the raw materials available and the results the manufacturer wishes to achieve. After the purest of raw materials are mixed and prepared, the product is shaped and molded into the desired items and placed through a series of firings at extremely high temperatures and for long periods of time. The number of firings is often determined by the nature of the design sought. As with stoneware, the body becomes vitrified; which means the body fuses, becomes nonabsorbent, and very strong. Unlike stoneware, china becomes very white and translucent.
China vs. Porcelain
Many people are confused as to the difference between “china” and “porcelain.” Actually, the two terms describe the same product. The term “china” comes from its country of origin, and the word “porcelain” comes from the Latin word “porcella,” meaning seashell. It implies a product which is smooth, white, and lustrous. The term “porcelain” is preferred in Europe while “china” is favored in the United States. China is “at the top of the list” of ceramic products because of its delicate beauty, and the extreme care and skill taken to produce it. China is very delicate in appearance only, as it is known for its great strength and resistance to chipping, which results from a high firing temperature.
In making bone china, calcified bone is used as a refractory material and the firing temperature is lower. Bone china is usually thinner and the glaze is smoother than porcelain china. The glaze, however, is not as durable as porcelain china since it is softer. “Bone china” starts the same way as porcelain china but includes an extra ingredient, bone ash. This is a white powdery substance and the byproduct of incinerated animal bone. Bone ash gives the body of the plate a unique milky white color. Bone ash adds translucency to the body of the dinnerware, and makes the dish stronger by making it softer. It’s true! By making the dinnerware less brittle, the bone ash makes it more resilient and less likely to break.
Ivory China/Ivory Bone China
Ivory china and ivory bone china are the same as described above. The only difference is that an ivory coloring is added to the mixture.
- Backstamp: Name, stamp, or signature of the manufacturer on the underside of the ware.
- Beading: Also called jewelling, features an enameled raised dot design.
- Bisque or Biscuit: Clayware fired once for hardening, but not yet glazed.
- Bone China: Contains up to 50% animal ash, mostly ox bone, which is burned and round to a fine powder.
- Casting: A process in which the slip is poured into a mold and set.
- Ceramics: Generic term referring to all ware made of earth materials and processed by firing or baking.
- China: Another generic term, usually referring to fine porcelain. Called china because it is the country credited with creating dinnerware.
- Clay: Raw material formed when rock breaks down either due to the weather or chemical processes.
- Coupe Shape: Plate lacking a shoulder, flat across the diameter, deliberately induced by sudden cooling.
- Crackledware (also known as a Reactive Glaze): Clayware surface marked by tiny cracks deliberately induced by sudden cooling.
- Decal: A design-bearing sheet applied to ware, resulting in transfer decoration (transferware). Firing makes the decal permanent.
- Embossing: Raised or molded decoration produced in the mold or formed separately and applied before firing.
- Engraving: Decorative technique of cutting the surface with wheels or sharp pointed tools by hand.
- Faceting: Decorative technique of cutting diamond-shaped or other patterns into surface.
- Firing: Baking process where all ceramics are subject to hardening, strengthening, or fusing.
- Gilding: Using gold or platinum to decorate dinnerware.
- Glaze: Glossy transparent or colored coating baked onto clayware to make it nonabsorbent and resistant to wear.
- Jiggering: Jiggering machines are used to shape plates.
- Kiln: Oven in which ceramics are fired or baked.
- Luster: Ceramic glaze coating, metallic in nature, which gives the finished piece an iridescent effect.
- Matte Finish: Flat glaze finish without gloss.
- Motif: Dominant feature in a design.
- Open Stock: Purchase of individual pieces rather than place settings.
- Porcelain: Hard, translucent clayware unusually consisting of 50% kaolin, 25% quartz, and 25% feldspar fired at high temperatures. Kaolin provides plasticity, durability, and consistency and influences the whiteness of the body; quartz provides stability; and feldspar provides vitrification.
- Shoulder: Raised rim of a plate.
- Silica: One of our most abundant materials and a vital ingredient in dinnerware. Basic component of glazes.
- Slip: Mixture of clay and water used to produce the body and decoration.
- Slip Coating: Layer of slip applied to a body for decorative effect.
- Stoneware: Dense clay fired at 2400 degrees. Stoneware is generally glazes in subdued earthy tones giving a hand-crafted look. Porous and chip-resistant.
- Vitrification: During firing, silica is changed into glass and bonds all ingredients together. The proportion of a glossy bond increases and its porosity lowers. China is fully vitrified.
Courtesy Noritake and Tableware Today