Porcelain or Bone?

Porcelain and bone china are the two ceramic bodies most often used to define china. Not only are the two not the same; neither is the exclusive domain of fine china. In fact, what fine china is depends on the company who is selling it.. For some, it generically higher-end china; for others, I.e. bone china companies, the term is used to define their lower-priced porcelain lines, patterns, or shapes. Ask you vendor just what their fine china designation means.

Using your eyes as a guide is another tip-off. Porcelain is naturally a blue-gray white, while bone china is a translucent white or ivory-white. And though the addition of animal bone ash achieves bone china’s whiteness, thin porcelain is also translucent, often fudging the line between the two.

Bone China contains up to 60 percent animal ash (mostly ox bone), which is burned and ground into a fine powder, then added to the base batter of white clay. Porcelain is made from kaolin (a white clay that melts at high temperatures), quartz (a stabilizer) and feldspar (a cement-like mineral agent that binds). While porcelain technology was first brought to Europe (and jealously guarded) by Meissen; it was Josiah Spode who set the ultimate standard for bone china around 1800 in England: six parts bone ash to four parts chinastone – a stand still adhered to today.

Taking the Heat

The firing processes of the two mediums differ, too. Bone china, strong because of the bone ash additive, has a high-heat first firing and a lower-heat glaze firing that produces a softer glaze (one that will show knife cuts after time and adopt a patina). Porcelain, on the other hand, has a lower-heat first firing and a high-temperature glaze firing that melts the glaze into the body and creates vitreous, glass-like product able to with modern conveniences as dishwashers and microwave ovens.

Even within the bone china and porcelain ranges there are differences in construction, consistencies and clays. It did not take Europeans long to realize that the porcelain they produced was not exactly what they had seen in the Far East. The difference? The quality of the clay. Oriental clay consists of decomposed granite (silicon and alumina); while Western clays were less mineral rich. China clay, as it as come to be known, was subsequently discovered in Limoges, France; Saxony, Germany; and in England's Cornwall and Devon sectors, ultimately guaranteeing these locales as home to many porcelain makers.

Excerpt by: Gifts & Decorative Accessories