In its workable form, clay is a very "plastic" material meaning that it is highly capable of being shaped and molded. Once molded, either "hand built" or "thrown" on the potter's wheel, it will retain the imprints and shaping of the potter's hands, gradually becoming stiffer and harder as water evaporates from the clay. Once this "greenware" is completely dry, it is very brittle and requires careful handling. To achieve a durable, lasting creation, the potter must now kiln fire his work. This concentrated application of heat causes chemical changes which render the clay hard, rock-like and durable. In order to make the resulting "bisque" ware more attractive and functional, the potter next coats his work with glaze and kiln fires it once again.

The glaze is a mixture of chemicals, minerals and water which when deposited over the pottery and fired to the correct temperature, fuses over the forms to create a glass coating. Metallic oxides and glaze stains added to the glaze give colouring and most potters develop their own special recipes for glaze mixtures - each creating unique colour combinations which identify the work from that of other potters. The range of colours is enormous - tin oxides produces a white glaze, manganese carbonate yields purple, red from iron oxide, brown from iron chromate. The list goes on and as oxides themselves are mixed together the shades of colour expand further.

Currently, we have many capable people "potting" around our province. You'll see their works at craft shops, craft shows, flea markets and perhaps you will be baffled by the variety and names of their products. Basically, you will be seeing 3 types of pottery - earthenware, stoneware and porcelain and these represent 3 different types of products.

Earthenware pottery is made from common clay, our local source in Nova Scotia being the Lantz area where L. E. Shaw Ltd. uses the same clay for its brick products. The clay reaches its rock like "bisque" form at a relatively low kiln temperature, between 1050 and 1150 degrees C . The iron in this type of clay produces a pottery which is red or brown in colour - our Lantz clay is quite reddish. Earthenware pottery is quite porous, so it won't hold water unless glazed, but this makes it the perfect product for wine coolers, butter coolers, clay bakers, all of which are soaked in water before use. The unglazed earthenware will soak up the water and in the case of a clay baker, release it again as steam as you cook your roast in it.

Stoneware pottery that is unglazed is, by contrast, non porous. Fired at a higher temperature(1200-1300 degrees C), the particles in this type of clay begin to "vitrify" or crystallize together forming an impervious and very strong product. Although an unglazed stoneware cup will hold water, most potters glaze their stoneware pieces to give it a smoother and more attractive appearance. Perhaps your grandmother had old stoneware jugs and crocks with clear glazes?

Porcelain pieces are made from a white clay composed of felspar, china clay and quartz. It is a very soft, putty-like, fine grained clay requiring special skill to handle and mold into shape. This clay is high-fired at temperatures of 1300 degrees C or more and upon firing, the clay and glaze totally fuse, producing a fully vitrified product. The chemical reaction occurring during firing forms a structure of interlocking crystals between the clay particles thus making the finished pieces non porous. Porcelain also becomes translucent upon firing giving it the appearance of fine, smooth bone china. It is the aristocrat of pottery pieces!