Hobbies And Interests
Art
Art clay is rarely used just as it is found in the earth because naturally occurring clay is such a mixture of different minerals that it rarely has the kind of plasticity necessary to hold a shape while being manipulated. Manufacturers modify the clay contents to attain the desired consistency for the type of application. Art clay is categorized by the temperature required to fire it in a kiln, or even whether it requires firing at all.
Edible
Most clay that is eaten is done so for medicinal reasons, and it is often combined with other palliative ingredients. Kaolin is a simple, coarse white clay, ill-suited for artwork but an ideal bulking agent. It is a main ingredient in Kaopectate, a mild anti-diarrhea medicine. Smectite (also called bentonite) clays have absorptive and adsorptive properties that allow them to remove toxins and bacteria. The best-known of the smectite types is montmorillonite.
Cosmetic
Smectite clays are also used cosmetically to draw out impurities and toxins in the skin. Mud masks are actually made of clay mixed with enough water to be spreadable, although they also contain mud and other ingredients. The added water boosts the clay's absorptive and adsorptive properties, which are the result of negatively charged ions in the clay. Toxins stick to the outside of the clay and are also pulled into the spaces between the clay molecules.
Industrial
Various clays are used in research and industry, with the application determining the type of clay used. Brick, tile, stoneware and glazed product manufacturers often use kaolinite clays, as do makers of aqueous-based paints and natural and synthetic polymers. Smectitic clays swell to several times their original size in water, helping to form walls when oil wells are drilled. Other clay types, sometimes called fuller earths, help purify petroleum and vegetable oils. Clays are beginning to find use in environmental cleanup because they can absorb impurities.