A Quick Guide to Porcelain

Porcelain has been in use for thousands of years and has been used for different purposes all over the globe. The manufacture of porcelain originated in ancient China. Chinese potters developed the method for making and firing porcelain as an extension of their work producing stoneware items, such as pots, tea sets and assorted crockery.Porcelain is a ceramic material which is made by heating a mixture of clay and other raw materials to high temperatures in a kiln. The temperatures inside the kiln vary between 1 200 and 1 400 degrees Celsius depending on the raw materials used. These high temperatures have the effect of turning certain minerals within the clay mixture into glass, resulting in the smooth texture, strength, impermeability and strength of porcelain.

There are three kinds of porcelain, namely hard paste, soft paste and bone china. The generic term for porcelain, 'china', arose due to the fact that the method of mixing and firing porcelain was originally developed in China during the Tang Dynasty which lasted from the year 618 to 906.

Hard paste porcelain has its origins in ancient China in the 9th Century when potters began using kaolin clay which was glazed with a feldspar solution in their work. Hard paste porcelain generally cracks and chips quite easily due to the inflexibility and strength of the mixture used. The strength of hard paste porcelain results in dishes and bowls made of hard paste porcelain being insusceptible to stains from foods and liquids being kept in them and makes hard paste porcelain items difficult to scratch. English potter's only began using hard paste pottery in 1770, long after the Chinese had mastered the material and techniques.

Prior to 1770, English and European potters made use of soft paste porcelain in their work in an attempt to replicate imported Chinese hard paste porcelain wares. Soft paste porcelain differs from hard paste porcelain in terms of the porcelain's composition. Soft paste clay is made up of a mixture of white clay and pulverized glass. Unlike hard paste porcelain, soft paste porcelain scratches and chips quite easily.

Bone china, interestingly, was not developed in China. Rather, bone china was developed in Staffordshire, England by Josiah Spode II and quickly became the main type of porcelain in the region. The region of Stafforshire  to this day porduces the vast majority of English porcelain, thanks to the minerals found in the area.

Bone china earned its name due to the fact that it is a mixture of white clay, feldspar and burned cattle bones. Thanks to this addition bone china does not crack or chip as easily as the other types of porcelain. 

Bone china is easily distinguished from other types of porcelain because it is more translucent than hard and soft paste porcelain. When held up to a light bone china items let a large amount of light pass through the porcelain. The value of porcelain items is dependent on a number of variables, including the potter's marks, decoration and shape. The potter's mark is similar to a hallmark on a piece of silver, and is a marking or stamp commonly found on the base of the piece which identifies the company or potter that made the piece and provides an approximate date of manufacture. The hallmark, combined with the overall condition of the piece provide the most accurate basis upon which the value of the item can be evaluated.