Bone China Ware - The Facts

Ironically, bone china was originally developed as a substitute for real (or 'hard paste') porcelain in the late 1700’s.

Porcelain is one of three types of pottery - the other two being earthenware and stoneware. Any other fancy names (majolica, delftware, jasperware etc) are just derivatives of one of these three, mainly used to describe decoration methods.

The best china has always been the thinnest and most refined.

Bone china ware is very thin and very refined, yet is the toughest of porcelains. Oh, and yes, it does contain bones.

Processed bone ash makes up the biggest part of the recipe, the rest being kaolin (china clay) and petuntse (petuntse is also known as feldspar or China stone).

Production usually involves a two stage firing where the first, bisque, is without a glaze giving a translucent product and then there is a second glaze (or glost) firing at a lower temperature.

Types of porcelain

Hard-Paste Porcelain

The resultant body is then fired at high temperatures. The clay body and the glaze melt together (vitrify) so that when hard-paste is broken, you can’t tell the body from the glaze. The colors lie on top of the glaze. Porcelain will allow bright light to pass through it.

The downfall of hard porcelain is despite its strength it chips fairly easily and is tinged naturally with blue or grey. It is fired at a much higher temperature than soft-paste porcelain and therefore is more difficult and expensive to produce.

The recipe for hard-paste porcelain is as follows: 50% china clay, 30% china stone, 20% flint. Firing: Biscuit temperature 900 C - 1000 C. Glost firing 1350 C - 1400 C.

Soft-Paste porcelain

As it turned out, the inability to hold liquids unless glazed (not being fully vitrified) didn’t matter in its application for decorative art. The colors merge with the glaze to produce a wonderful silk-like effect, very appealing to the eye, and to collectors.

Soft paste porcelain contains kaolin (china clay) and petuntse (petuntse is also known as feldspar or China stone) but also includes 'frit' - a glassy substance that is a mixture of white sand, nitre, alum, salt and gypsum.

Lime and chalk were used to fuse the white clay and the frit and then fires at lower temperatures. As a result the body is granular since the ingredients do not melt together (vitrify) and therefore is weaker than bone china and liable to chip more readily.

Unlike bone china ware, and hard paste porcelain, soft-paste porcelain can be filed down. Firing temperatures: biscuit 1200 C - 1300 C. Glost 1050 C - 1150 C.

Bone China Ware

For an artist, the privilege of working with such a maker is difficult to put into words. The original principles of the founder, Dr Wall, to which they can attribute their centuries of success, still run through the factory to this day.

The initial development of bone china is attributed to Josiah Spode II (son of the original Spode), who introduced it around 1799. When Josiah Spode 11 discovered bone china, he couldn’t have dreamed what a magnificent medium he was creating. Bone china is extremely hard, intensely white and will allow light to pass through it.

The standard English body basic formula remains: six parts bone ash, four parts china stone, and three and a half parts china clay. First or biscuit firing 1200 C - 1300 C. Second, Glost 1050 C - 1100 C.

china manufacturers (A-Z guide to who’s who)

antique bone china (the famous old factories)

English Bone China (a view from the inside)

bone china manufacturers (the new generation - since 1950)

Wedgwood (the legend)