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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 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, 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 ...

flint clay

(Encyclopedia)flint clay: see fire clay.

boulder clay

(Encyclopedia)boulder clay: see drift.

Clay, Cassius Marcellus

(Encyclopedia)Clay, Cassius Marcellus, 1810–1903, American politician and diplomat, b. Madison co., Ky. Although he came from a slaveholding family, Clay early came to abhor the institution of slavery. In 1845 he...

Clay, Clement Claiborne

(Encyclopedia)Clay, Clement Claiborne, 1816–82, U.S. Senator (1853–61), b. Huntsville, Ala. A legislator and then a judge in his native state, he was twice elected to the U.S. Senate and became an ardent defend...

Clay, Lucius DuBignon

(Encyclopedia)Clay, Lucius DuBignon dəbĭnˈyən, dübēnyôNˈ [key], 1897–1978, American general, b. Marietta, Ga. A graduate of West Point and an engineering officer, he held many army administrative posts an...