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china clay

(Encyclopedia)china clay, one of the purest of the clays, composed chiefly of the mineral kaolinite usually formed when granite is changed by hydrothermal metamorphism. Usage of the terms china clay and kaolin is n...

clay

(Encyclopedia)clay, common name for a number of fine-grained, earthy materials that become plastic when wet. Chemically, clays are hydrous aluminum silicates, ordinarily containing impurities, e.g., potassium, sodi...

china marks

(Encyclopedia)china marks, potter's trademark or signature, incised in the plastic clay before firing or printed before glazing on the bottom of the piece to identify it as his product. The practice was adopted by ...

bone china

(Encyclopedia)bone china, variety of porcelain developed by English potters in the last half of the 18th and early 19th cent. The clay is tempered with phosphate of lime or bone ash. This innovation greatly increas...

China

(Encyclopedia)CE5 CE5 China, Mandarin Zhonghua Renmin Gongheguo [central glorious people's united country; i.e., people's republic], officially People's Repu...

flint clay

(Encyclopedia)flint clay: see fire clay.

Clay, Henry

(Encyclopedia)Clay, Henry, 1777–1852, American statesman, b. Hanover co., Va. In 1828, Clay again supported Adams for President, and Jackson's success bitterly disappointed him. Although he intended to retir...

clay pan

(Encyclopedia)clay pan: see hardpan.

fire clay

(Encyclopedia)fire clay, clay that has a high degree of resistance to heat. By the best standards it should have a fusion point higher than 1,600℃. The term “fire clay” is commonly held to exclude kaolin and ...

boulder clay

(Encyclopedia)boulder clay: see drift.