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Val d'Or

(Encyclopedia)Val d'Or väl dôr [key], town (1991 pop. 23,842), SW Que., Canada, SE of Rouyn-Noranda. It is a mining center. Gold was discovered in the region in 1909; copper, zinc, lead, and molybdenum are also m...

Truth or Consequences

(Encyclopedia)Truth or Consequences, city (1990 pop. 6,221), seat of Sierra co., SW N.Mex., on the Rio Grande between the Black Range (W) and Jornada del Meurto desert basin (E); inc. 1916 as Hot Springs, renamed 1...

fluorescence

(Encyclopedia)fluorescence flo͝orĕsˈəns [key], luminescence in which light of a visible color is emitted from a substance under stimulation or excitation by light or other forms of electromagnetic radiation or ...

caustic

(Encyclopedia)caustic, any strongly corrosive chemical substance, especially one that attacks organic matter. A caustic alkali is a metal hydroxide, especially that of an alkali metal; caustic soda is sodium hydrox...

hyperinsulinism

(Encyclopedia)hyperinsulinism, presence in the system of an above-normal amount of insulin, the substance secreted by the pancreas and needed by the body to utilize sugar. An increased amount of insulin in the body...

soil

(Encyclopedia)soil, surface layer of the earth, composed of fine rock material disintegrated by geological processes; and humus, the organic remains of decomposed vegetation. In agriculture, soil is the medium that...

topaz

(Encyclopedia)topaz tōˈpăz [key], aluminum silicate mineral with either hydroxyl radicals or fluorine, Al2SiO4(F,OH)2, used as a gem. It is commonly colorless or some shade of pale yellow to wine-yellow; pale bl...

gypsum

(Encyclopedia)gypsum jĭpˈsəm [key], mineral composed of calcium sulfate (calcium, sulfur, and oxygen) with two molecules of water, CaSO4·2H2O. It is the most common sulfate mineral, occurring in many places in ...

gum, colloidal plant substance

(Encyclopedia)gum, term commonly applied to any of a wide variety of colloidal substances somewhat similar in appearance and general characteristics, exuded by or extracted from plants. In this classification, howe...

pigment

(Encyclopedia)pigment, substance that imparts color to other materials. In paint, the pigment is a powdered substance which, when mixed in the liquid vehicle, imparts color to a painted surface. The pigments used i...