Geneva coffee saucer demitasse

Bone china

Bone china is a kind of porcelain body first produced in Great Britain in which calcined ox bone, bone ash, is an essential part. It is distinguish by supreme whiteness, translucency and strength. geneva coffee saucer/demitasse may be an example of this procedure.

The initial use of bone ash in ceramics is associated with Thomas Frye in seventeen-forty-eight in which he used it to make a type of soft-paste porcelain. In In the late 18th century, Josiah Spode undertook further developments, and duly popularized it, by combining it with China stone, kaolin and china clay to compete against the imported Oriental porcelain.

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

The production of bone china commonly makes use of 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 temperature less than 1080°C (1976°F). geneva coffee saucer/demitasse is probably made using this method.

Soft-paste porcelain

Soft-paste porcelain is a kind of porcelain and therefore a ceramic product.

Its origin dates from the early pursuits by European potters to copy Chinese porcelain by using compounds of china clay and ground-up glass or frit; lime and soapstone were also known to have been employed in some mixtures. As these initial concoctions suffered from high pyroplastic collapse, or slumping in the oven at high temperature, it was uneconomical to produce them. Compositions were later used based on quartz, kaolin, nepheline syenite, feldspars 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 mixture of the feldspathic rock petuntse and kaolin fired at very high temperature. It was first produced in China around the 9th century.

The secret of its manufacture was not known in Europe until the early eighteenth century, when Böttger of Meissen, Germany found the formula. Regardless of attempts to keep it secret, the process was employed by other German ceramic potteries and in time became well used throughout Europe.

Hard-paste porcelain is known to be fired at a range of temperatures to manufacture a myriad of unique end results. Depending on the firing process, hard-paste porcelain can be manufactured to resemble earthenware or stoneware. But most of the time, it is not necessary to utilize hard-paste porcelain for these lower temperature ceramics. Hard-paste porcelain can be used to create porcelain bisque, a hard crystalline material fired at extremely high temperatures in a pressure controlled environment. This approach manufactures a translucid 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, Precious Moments and Lladro make use of hard-paste porcelain simply for this reason, this could include geneva coffee saucer/demitasse.