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fluorite
(Encyclopedia)fluorite flo͞oˈərspär [key], mineral appearing in various colors, e.g., green, yellow-brown, rose, and red. Chemically, it is calcium fluoride, CaF2. Its crystals, commonly cubic, are transparent ...fluorspar
(Encyclopedia)fluorspar: see fluorite.spar
(Encyclopedia)spar. For dogtooth spar, see calcite; for fluorspar, see fluorite; for heavy spar, see barite; for satin spar, see calcite and gypsum. See also Iceland spar and feldspar. ...fluorine
(Encyclopedia)fluorine flo͞oˈərēn, –rĭn [key], gaseous chemical element; symbol F; at. no. 9; at. wt. 18.9984; m.p. −219.6℃; b.p. −188.14℃; density 1.696 grams per liter at STP; valence −1. Fluorin...Gangwon
(Encyclopedia)Gangwon or Kangwon gängˈwŭnˈ [key], province, N South Korea. Chuncheon is the capital. The 38th ...halogen
(Encyclopedia)halogen hălˈəjĕn [key] [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromin...hardness
(Encyclopedia)hardness, property of matter commonly described as the resistance of a substance to being scratched by another substance. The degree of hardness is relative, different substances being compared with o...Guanajuato, state, Mexico
(Encyclopedia)Guanajuato gwänähwäˈtō [key], state, 11,805 sq mi (30,575 sq km), W central Mexico, on the ...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 ...calcium
(Encyclopedia)calcium kălˈsēəm [key] [Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.078; m.p. about 839℃; b.p. 1,484℃; sp. gr. 1.55 at 20℃; valence +2. Calcium is a malleable, ...Browse by Subject
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