leucite

leucite
A mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, Leucite is a potassium feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, Leucite weathers rapidly and can only be seen as inclusions in freshly broken rock. ,Chemical composition: Potassium aluminum subsilicate, KAlSiO ,Physical properties: Mohs Hardness: 5.5-6.0 Specific gravity: 2.4-2.5 Color: Gray to white to colorless Luster: Glassy, but rapidly weathers to a dull surface Fracture: Conchoidal Cleavage: Imperfect dodecahedral Habit: Tetragonal-trapezohedral (pseudo-isometric)
See Also: rock, feldspar

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  • Leucite — is a rock forming mineral composed of potassium and aluminium tectosilicate K [AlSi2O6] . Crystals have the form of cubic icositetrahedra but, as first observed by Sir David Brewster in 1821, they are not optically isotropic, and are therefore… …   Wikipedia

  • Leucite — Catégorie IX : silicates[1] Cristaux de leucite Général …   Wikipédia en Français

  • leucite — [ løsit ] n. f. et m. • 1796; de leuc(o) et ite 1 ♦ N. f. Minér. Silicate de potassium et d aluminium, blanc à l éclat vitreux, que l on trouve dans les roches volcaniques. 2 ♦ N. m. (1890) Bot. ⇒ plaste. ● leucite nom masculin Synonyme ancien de …   Encyclopédie Universelle

  • Leucite — Leu cite (l[=u] s[imac]t), n. [Gr. leyko s white: cf. F. leucite.] [1913 Webster] 1. (Min.) A mineral having a glassy fracture, occurring in translucent trapezohedral crystals. It is a silicate of alumina and potash {KAlSi2O6}. It is found in the …   The Collaborative International Dictionary of English

  • leucite — s. f. [Mineralogia] Espécie de feldspato de lustre vítreo.   ♦ Grafia no Brasil: leucita …   Dicionário da Língua Portuguesa

  • leucite — [lo͞o′sīt΄] n. [Ger leucit, now leuzit (< Gr leukos, white: see LIGHT1) + it, ITE1] a white or gray mineral, KAlSi2O6, found in potassium rich igneous rocks; potassium aluminum silicate …   English World dictionary

  • leucite — leucitic /looh sit ik/, adj. /looh suyt/, n. a whitish or grayish mineral, potassium aluminum silicate, KAlSi2O6, found in alkali volcanic rocks. [1790 1800; < G Leukit. See LEUCO , ITE1] * * * One of the most common feldspathoid minerals,… …   Universalium

  • leucite — 1leu·cì·te s.f. TS mineral. minerale di colore bianco del gruppo dei feldspatoidi, costituito da alluminosilicato di potassio, componente abbondante di alcune rocce effusive e ottimo substrato di suoli fertili {{line}} {{/line}} DATA: 1817. ETIMO …   Dizionario italiano

  • leucite — leucitas statusas T sritis chemija apibrėžtis Mineralas. formulė K[AlSi₂O₆] atitikmenys: angl. leucite rus. лейцит …   Chemijos terminų aiškinamasis žodynas

  • leucite syenite — Syenite Sy e*nite, n. [L. Syenites (sc. lapis), from Syene, Gr. ?.] (Min.) (a) Orig., a rock composed of quartz, hornblende, and feldspar, anciently quarried at Syene, in Upper Egypt, and now called {granite}. (b) A granular, crystalline, ingeous …   The Collaborative International Dictionary of English

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