Grasmere tea saucer

Bone china

Bone china is a type of porcelain body initially used in the UK in which calcined ox bone, bone ash, is a major ingredient. It is distinguish by supreme whiteness, translucency and strength. grasmere tea saucer may be an example of this process.

The initial use of bone ash in ceramics is assigned to Thomas Frye in seventeen-forty-eight in which he used it to introduce a kind of soft-paste porcelain. In At the close of the 18th century, Josiah Spode continued with further developments, and consequently popularized it, by mixing it with China stone, kaolin and china clay to compete against the imported Oriental porcelain.

The initial basic formula of six parts bone ash, four parts china stone, and three and a half parts china clay is still the standard English body.

The manufacture of bone china ordinarily employs a two stage firing process where the first "biscuit" is fired without a glaze at 1280°C (2336°F) giving a translucent product and then it is glost, or glaze, fired at a lower heat below 1080°C (1976°F). grasmere tea saucer is probably produced using this process.

Soft-paste porcelain

Soft-paste porcelain is a type of porcelain and therefore a ceramic material.

Its origin dates from the early ventures by potters from Europe to imitate Chinese porcelain by using combinations of china clay and frit or ground-up glass; soapstone and lime were also known to have been included in some concoctions. As these first formulations were prone to high pyroplastic deformation, or slumping in the kiln at high temperature, they were not economical to manufacture. Compositions were later produced based on quartz, feldspars, nepheline syenite, kaolin and other feldspathic rocks. These were technically superior and continue in production today.

Hard-paste porcelain

Hard-paste porcelain is a hard, dense ceramic that was originally manufactured from a formulation of the feldspathic rock petuntse and kaolin fired at very high temperature. It was first made in China around the ninth century.

The secret of its manufacture was unknown in Europe until the early 1700s, when Böttger of Meissen, Germany discovered the formula. Regardless of attempts to keep it secret, the procedure was taken up by other German ceramic potteries and eventually became widely used throughout the whole of Europe.

Hard-paste porcelain is known to be fired at a range of temperatures to create a multitude of different end results. Depending on the firing approach, hard-paste porcelain can be manufactured to resemble earthenware or stoneware. But most of the time, it is not necessary to employ hard-paste porcelain for these lower temperature ceramics. Hard-paste porcelain can be used to make porcelain bisque, a hard crystalline product fired at extremely high temperatures in a pressure controlled environment. This method makes a semiopaque bright white ceramic. Unlike other bisque ceramics, porcelain bisque is almost impermeable by water, therefore it becomes unnecessary to glaze the body before painting. Manufacturers such as Hummel, Precious Moments and Lladro use hard-paste porcelain just for this reason, this could include grasmere tea saucer.