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Koschetzki
Ceramic
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A B C D E F G H I J K L M N O P Q R S U V W X Y Z
 
A
Ash Glaze
The chemical composition of wood ash is similar to that of a glaze, primarily alkaline fluxes, alumina and silica.  This could be called a natural glaze, however few ash types make a glaze alone and they are usually mixed with other glaze materials; however in a wood fired kiln the action of the ash can produce a glazed surface upon the fired objects.
 
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B
Ball Clay
A sedimentary clay that will withstand high firing temperatures. Plastic in quality.
 
Bisque
Clay that has been given a preliminary firing to render it hard enough for further work such as decoration and glazing.
 
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C
 Ceramics
 An earth material treated by heat to form and produce objects or materials of benefit to humanity.  Such as bricks, glass cement, pottery, sculpture, computer chips, insulation, etc..  The list goes on and on.
 
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Celadon
A gray-green glaze, usually pale in color.
 
China
Porcelain. The first porcelain imported into Europe was from China.
 
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China Clay
Kaolin. A white clay being close to the chemical ideal of pure clay or kaolinite, lacking the impurities that color other clay deposits.
 
Clay
Hydrated silicate of aluminium, or mud, a plastic material when wet capable of being molded into shapes that become hard and impervious to water after being heated.
 
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Clay Body
A clay formula that is designed to meet specific criteria, can be natural occurring or made.
Coiling
Rolled clay in flat form or with a rounded section that welds to itself.  Coils are used to build clay forms, one of the the three basic hand building techniques. 
 
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Cone
Cones are small objects composed of ceramic materials.  They are placed into a kiln to be fired and reveal the progression of heat work on clay objects during the firing. Cones, are manufactured by the Orton Ceramic Foundation in the US.
 
Crackle
Cracks in a glaze surface resulting when the thermal expansion of the glaze do not match the thermal expansion of the clay body, used as a decorative motif at times. 
 
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Crawling
A glaze fault, shrinkage or retraction of the glaze during drying and firing, causing exposed areas of clay body after firing. Can be used for a glaze effect called leopard skin.
 
Crazing
A fine network of cracks in the glaze usually caused by uneven contraction and expansion of the clay body and the glaze during changes of temperature. In some pottery this is a design feature rather than a fault (See - Crackle).
 
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D
Dunting
Cracking or breaking of fired objects, caused by silica inversions at lower temperatures.
 
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E
Earthenware
Objects that are porous when unglazed, up to 15% water absorption. Usually fired at low temperatures. Earthenware is softer and more easily damaged than stoneware.
 
Engobe
A liquid clay slip containing metallic oxides or glaze stains applied to clay objects before firing for decoration.  They can be covered with a glaze or used alone.
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F
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G
Glaze
Glassy alumina silicate surface applied to clay and fused by heat, composed of earthy materials and metallic oxides for color.
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H
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I
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J
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K
Kiln
A studio furnace for firing clay; studio kilns can achieve temperatures of up to 2500F (1371C) depending on their construction materials.  They can be fueled using carbon, organic matter or electricity
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L
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M
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N
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O
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P
Porcelain
Dense and strong high fired clay that has a substantial glaze clay interface and exhibits a water absorption of less then 1%, usually white.
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Q
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R
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S
Stoneware
High fired clay that exhibits a noticeable clay glaze interface and has a water absorption of less then 5%, can vary in color.
c Koschitzki
c Koschetzki