Royal gold open vegetable tureen

Bone china

Bone china is a kind of porcelain body initially produced in the UK in which calcined ox bone, bone ash, is an essential part. It is distinguish by extremely high whiteness, strength and translucency. royal gold open vegetable tureen may be an example of this process.

The first use of bone ash in ceramics is credited to Thomas Frye in seventeen-forty-eight in which he used it to introduce a type of soft-paste porcelain. In Towards the end of the eighteenth century, Josiah Spode carried on with further developments, and duly popularised it, by combining it with kaolin, China stone and china clay to compete with the imported Oriental porcelain.

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

The production of bone china mostly involves a 2 stage firing where the initial "biscuit" is fired without a glaze at 1280°C (2336°F) giving a semitransparent product and then it is glaze, or glost, fired at a lower temperature below 1080°C (1976°F). royal gold open vegetable tureen is probably manufactured using this technique.

Soft-paste porcelain

Soft-paste porcelain is a type of porcelain and consequently a ceramic product.

Its origin dates from the first trials by European potters to replicate Chinese porcelain by employing compounds of china clay and ground-up glass or frit; lime and soapstone were known to have also been included in some combinations. As these initial formulations were prone to high pyroplastic deformation, or slumping in the oven at raised temperature, it was uneconomical to manufacture them. Compositions were later used based on quartz, feldspars, nepheline syenite, kaolin and other feldspathic rocks. These were technically superior and are still in production today.

Hard-paste porcelain

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

The secret of its manufacture was unknown in Europe until the early eighteenth century, when Böttger of Meissen, Germany found the formula. Despite attempts to keep it secret, the procedure was taken up by other German ceramic factories and finally became widely known throughout Europe.

Hard-paste porcelain can be fired at a range of temperatures to manufacture many unique end results. Depending on the firing method, hard-paste porcelain can be made to resemble stoneware or earthenware. But mainly, it is unnecessary to utilize hard-paste porcelain for these lower temperature ceramics. Hard-paste porcelain can be employed to create porcelain bisque, a hard crystalline material fired at extremely high temperatures in a pressure controlled environment. This approach produces a semiopaque bright white ceramic. Unlike other bisque ceramics, porcelain bisque is almost inpenetrable by water, therefore it becomes unnecessary to glaze the body before painting. Manufacturers such as Hummel, Lladro and Precious Moments make use of hard-paste porcelain just for this reason, this could include royal gold open vegetable tureen.