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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...

flint clay

(Encyclopedia)flint clay: see fire clay.

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 ...

boulder clay

(Encyclopedia)boulder clay: see drift.

Frick, Henry Clay

(Encyclopedia)Frick, Henry Clay, 1849–1919, American industrialist, b. Westmoreland co., Pa. He worked on his father's farm, was a store clerk, and did bookkeeping before he and several associates organized (1871...

Folger, Henry Clay

(Encyclopedia)Folger, Henry Clay fōlˈjər [key], 1857–1930, American industrialist and collector of Shakespeareana. His connection with Standard Oil companies, beginning in 1879, continued until his retirement ...

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...