The only manufactured translucent substance then known was , for example) should have been used as a substitute for porcelain.The nature of glass, however, made it impossible to shape it by any of the means used by the potter, and a mixture of clay and ground glass was eventually tried.It is similar to the wheel in appearance except that the head consists of a plaster mold shaped like the inside of an object, such as a plate.As it revolves, the interior of the plate is shaped by pressing the clay against the head, while the exterior, including the footring, is shaped by a profile (a flat piece of metal cut to the contour of the underside of the plate) brought into contact with the clay.Porcelain made in this way resembles that of the Chinese only superficially and is always termed soft, or artificial, porcelain.The date and place of the first attempt to make soft porcelain are debatable, but some Middle Eastern pottery of the 12th century was made from glaze material mixed with clay and is occasionally translucent (, substituted ground feldspathic rock for the ground glass in the soft porcelain formula.
Generally, bone china is most popular for Raw clay consists primarily of true clay particles and undecomposed feldspar mixed with other components of the igneous rocks from which it was derived, usually appreciable quantities of quartz and small quantities of mica, oxides, and other substances.
The Chinese, on the other hand, define porcelain as any ceramic material that will give a ringing tone when tapped.
None of these definitions is completely satisfactory; for instance, some thinly potted stonewares are slightly translucent if they have been fired at a high temperature, whereas some heavily potted porcelains are opaque.
The line of demarcation between the two classes of vitrified materials—stoneware and porcelain—is extremely vague.
In the Western world, porcelain is usually defined as a translucent substance—when held to the light most porcelain does have this property—and stoneware is regarded as partially vitrified material that is not translucent.