abstract
| - Historically, "hard-paste" referred to the Asian porcelains that had been prepared from the aforementioned raw materials. The secret of its manufacture was not known in Europe until 1709, when Johann Friedrich Böttger of Meissen, Germany discovered the formula. Despite attempts to keep it secret, the process spread to other German ceramic factories and eventually throughout Europe. From 1712, the French Jesuit Francois Xavier d'Entrecolles described the Chinese process of manufacturing porcelain in his letters to Europe. Hard-paste, or just hard porcelain, now chiefly refers to formulations prepared from mixtures of kaolin, feldspar and quartz. Other raw materials can also be used and these include pottery stones, which historically were known as petunse although this name has long fallen out of use. Hard-paste porcelain is now differentiated from soft-paste porcelain mainly by the firing temperature, with the former being higher, to around 1400°C, and the latter to around 1200°C. Depending on the raw materials and firing methods used, hard-paste porcelain can also resemble stoneware or earthenware. Hard-paste porcelain can be utilized to make porcelain bisque, a type of porcelain. It is a translucent and bright, white ceramic. With it being almost impermeable to water it is unnecessary to glaze the body. Manufactures include Lladro, Hummel and Royal Worcester.
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