Kathy Fabian, age 12, of St. Paul, Minn., for her question

WHAT IS BONE CHINA?

Porcelain is called the aristocrat of ceramics because it is finely and delicately made. Where pottery is opaque, porcelain is translucent.

Porcelain comes from a Portuguese word meaning little pig. Portuguese traders at the end of the 17th century introduced Chinese porcelain to Europe, and since the pieces looked very much like shells, the name " porcellena"   a cowrie shell which was used for currency  seemed appropriate.

Fine porcelain today is often called china, and the reason for this is that the product originally came from China.

Bone china is a variety of porcelain which was developed in England during the 1st half the the 18th century. The clay used in this fine type of porcelain is tempered with phosphate of lime or bone ash. This additional material increased the strength of the china during and after the firing. ,

Ancient records show that the art of porcelain making was invented in China at about 185 B.C. First items were produced for the imperial household.

During the Tang Dynasty (A.D. 618 to 906) the Chinese potters perfected the production of animal figurines with horses, lions and camels the favorite subjects. Vases of exceptional beauty were also made at this time.

Greatest advances were made during the Ming Dynasty (1368 to 1644). In the imperial factory in a town near Nanking superb white porcelain was made. Also during this period cobalt blue and white, openwork porcelain and "grain of rice'' pieces were introduced.

Between the 10th and 16th centuries, the Persians also produced a translucent porcelain that was spectacularly beautiful.

All of the European countries eventually got into the porcelain making act. First was Italy, where Medici porcelains were produced. Then in the 17th century France and England came up with some beautiful work.

A giant step forward came in 1709 in Saxony where a man by the name of Johann Bottger founded the famous Meissen factory and produced porcelain that became known as Dresden china.

As the years passed, other famous lines of china were produced. Denmark became a leading manufacturer. In 1744, under the patronage of the czars, a factory was built in Leningrad.

After the special porcelain clay is cast into molds, it is allowed to dry before it is put into a kiln, or oven. It is baked at a comparatively low temperature and later dipped into glaze and fired gain, this time at a very high temperature.