Bone china and porcelain are two different types of ceramics. Like the difference between a muffin and a scone, these two types of ceramics use different ingredients and different firing methods.
Many people can't tell the difference or don't know the difference between bone china and porcelain. Bone china and porcelain have different processes for their production and they also have different recipes for the ingredients used to make each of them. The difference comes from the materials used to produce each type of ceramic and the process for making each.
Bone china goes by more than just one name. Bone china is sometimes called hard paste porcelain with bone ash even though it is not really porcelain and sometimes bone china is called fine china. Here is the real deal on bone china:
Bone china has a specific percentage of, what else?, bone or bone ash. In bone china, there is typically anywhere between 30% to 45% of animal bone used in the mixture. The type of animal bone that is used is most commonly cow bone, however other types of bone are also ground down and added to a bone china mixture. When making bone china, cow bone is ground down into an ash consistency and mixed with other ingredients. Materials used in the making of bone china include bone ash, quartz, kaolin, feldspar, silica, etc. This mixture is then either sculpted or molded into a desired shape or form and readied for firing. The formed piece is then fired in a temperature-monitored kiln. Most of the time, bone china is fired at a maximum temperature of 2228 degrees F or 1220 degrees C.
In addition to the use of animal bone, bone china's properties allow it to withstand being fired twice in the kiln. The first phase of kiln firing results in shrinkage of the bone china piece and the second phase allows the applied glaze of the piece of bone china to become one with the object itself. Some damage takes place during both phases of the kiln firing process. Some of the best known bone china is Staffordshire, Royal Doulton, Wedgwood, etc.
Porcelain does not use bone or bone ash as an ingredient in its mixture recipe. What's in it? Throughout history, people from different parts of the world produced various recipes and mixtures to make porcelain. For instance, the ancient Chinese used kaolin and pegmatite granite in their porcelain whereas the early European ceramists used clay, ground up glass, feldspar and other materials in their porcelain mixture. Porcelain is harder than bone china and it is fired in a kiln at a higher temperature than bone china. Porcelain is fired at approximately 2650 degrees F or 1454 degrees C. The most commonly known porcelain is Nippon porcelain made in Japan from 1891 to 1921 and is typically marked as such. Many pieces like oyster plates are made of porcelain.
Of course, just to confuse the issue, over time other manufacturers produced a third type of related ceramic that has some attributes of porcelain. For instance, a porcelain mixture that is fired at 2,200 degrees F or 1204 degrees C would be called fine china.
Fine china is not bone china and it is not porcelain. It is not bone china because there is no bone ash in it. It is not porcelain because it is not fired in a temperature as high as porcelain. In fact, fine china has the same ingredients at porcelain but it is not fired at as high a temperature as porcelain, nor is it as durable as porcelain either.
What to Look For
To the naked eye, bone china does not look bright white as fine china or porcelain. Bone china has a warmer off-white color than porcelain. The words bone china are often marked on the underside of a piece of bone china. Porcelain looks bright white to the naked eye and it is more durable and weighty when compared to bone china.
Recognizing the difference between bone china and porcelain is all about the ingredients in the ceramic mixture and its firing process. Both bone china and porcelain can be very valuable depending on the specifics of the piece, age, maker or manufacturer, and condition.
Get an online appraisal of your bone china or porcelain piece from Dr. Lori.