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<\/p>\nZbierkov\u00fdm predmetom mesiaca okt\u00f3ber je miner\u00e1l kalcit z\u00a0geologickej zbierky Pova\u017esk\u00e9ho m\u00fazea. Zemsk\u00e1 k\u00f4ra sa sklad\u00e1 z\u00a0r\u00f4znych horn\u00edn. V\u00e4\u010d\u0161inou s\u00fa to anorganick\u00e9 zl\u00fa\u010deniny zlo\u017een\u00e9 z\u00a0viacer\u00fdch prvkov. Zn\u00e1mych je pribli\u017ene 50 druhov miner\u00e1lov, ktor\u00e9 sa v\u00a0podstatnej miere podie\u013eaj\u00fa na stavbe horn\u00edn. Tieto naz\u00fdvame horninotvorn\u00fdmi. Skupinu m\u00e4kk\u00fdch miner\u00e1lov, ktor\u00e9 vznikaj\u00fa zl\u00fa\u010den\u00edm kovov\u00fdch prvkov s\u00a0uhl\u00edkom a\u00a0kysl\u00edkom, ozna\u010dujeme ako uhli\u010ditany. Niektor\u00e9 z\u00a0nich s\u00fa rozpustn\u00e9 v\u00a0morskej vode a \u017eivo\u010d\u00edchy ako m\u00e4kk\u00fd\u0161e ich vyu\u017e\u00edvaj\u00fa na budovanie pevn\u00fdch schr\u00e1nok. Tri hlavn\u00e9 uhli\u010ditanov\u00e9 miner\u00e1ly s\u00fa kalcit, aragonit a\u00a0dolomit. Najhojnej\u0161\u00ed je kalcit, miner\u00e1l uhli\u010ditanu v\u00e1penat\u00e9ho. Vyskytuje sa takmer vo v\u0161etk\u00fdch typoch horn\u00edn. Spolu s\u00a0aragonitom je pr\u00edtomn\u00fd v\u00a0istom druhu meteoritov, preto \u010das kry\u0161taliz\u00e1cie prv\u00fdch drobn\u00fdch kry\u0161t\u00e1lov, o\u00a0ve\u013ekosti nieko\u013eko 10 mikrometrov mo\u017eno datova\u0165 do vzniku slne\u010dnej s\u00fastavy. Kalcit m\u00e1 vy\u0161e 300 foriem, viac ako in\u00e9 miner\u00e1ly, vr\u00e1tane islandsk\u00e9ho kalcitu, ktor\u00fd sa pou\u017e\u00edval na v\u00fdrobu \u0161o\u0161oviek a jaskynn\u00e9ho kalcitu so \u0161picat\u00fdmi kry\u0161t\u00e1lmi, ozna\u010dovan\u00fdmi \u201epsie zuby\u201c.<\/p>\n
Vonkaj\u0161\u00edm vzh\u013eadom a\u00a0tvarom miner\u00e1lov sa zaober\u00e1 morfol\u00f3gia. Nerasty vyskytuj\u00face sa v\u00a0pr\u00edrode maj\u00fa z\u00e1konit\u00fd vzh\u013ead z\u00e1visl\u00fd od vn\u00fatornej stavby miner\u00e1lu a\u00a0ozna\u010duj\u00fa sa ako kry\u0161t\u00e1ly. S\u00fabor v\u0161etk\u00fdch pl\u00f4ch a\u00a0ich zoskupenia na kry\u0161t\u00e1li naz\u00fdvame kry\u0161t\u00e1lov\u00fdm tvarom. Prevl\u00e1daj\u00faci rozmer, relat\u00edvna d\u013a\u017eka a\u00a0\u0161\u00edrka pl\u00f4ch a\u00a0prevl\u00e1daj\u00faci tvar ur\u010duj\u00fa celkov\u00fd vzh\u013ead \u2013 habitus kry\u0161t\u00e1lu. Kalcit m\u00f4\u017ee ma\u0165 celistv\u00fd, zrnit\u00fd alebo kvap\u013eov\u00fd habitus. Vytv\u00e1ra tabu\u013ekovit\u00e9, st\u013apcovit\u00e9, ihli\u010dkovit\u00e9, plytk\u00e9 a\u017e ostr\u00e9 rombo\u00e9dre (klence) \u010di pseudokubick\u00e9 tvary. Kry\u0161talizuje v\u00a0trigon\u00e1lnej s\u00fastave. Typick\u00e1 je pre\u0148 dokonal\u00e1 \u0161tiepate\u013enos\u0165 a\u00a0tvrdos\u0165 na 3. stupni Mohsovej \u0161k\u00e1le tvrdosti. Be\u017ene je bezfarebn\u00fd a\u017e biely, vyskytuje sa v\u0161ak aj v\u00a0odtie\u0148och sivej, zelenkastej, \u017eltej a\u00a0medovej farby.<\/p>\n
Po\u010das hist\u00f3rie mal r\u00f4zne pomenovania. Najzn\u00e1mej\u0161ie z\u00a0nich je islandsk\u00fd v\u00e1penec. N\u00e1zov je odvoden\u00fd z\u00a0nemeck\u00e9ho \u201ecalcit\u201c, \u010do je term\u00edn vytvoren\u00fd v\u00a019. storo\u010d\u00ed z\u00a0latinsk\u00e9ho slova calx (v\u00e1pno). V\u00a0roku 1808 Humphrey Davy izoloval z\u00a0nehasen\u00e9ho v\u00e1pna elektrolytick\u00fdm procesom nov\u00fd prvok a\u00a0nazval ho kalcium. N\u00e1sledne mineral\u00f3g Wilhelm Karl von Haidinger v\u00a0roku 1845 pou\u017eil slovo kalcit pre v\u0161etky v\u00fdskyty uhli\u010ditanu v\u00e1penat\u00e9ho.<\/p>\n
Kalcit sa nach\u00e1dza v\u00a0magmatick\u00fdch hornin\u00e1ch, v\u00a0dr\u00fazach ge\u00f3d (dut\u00edn), v\u00a0bazaltoch a\u00a0hornin\u00e1ch im podobn\u00fdm. Kr\u00e1sne kry\u0161t\u00e1ly tohto miner\u00e1lu sa vyskytuj\u00fa v\u00a0hydroterm\u00e1lnych \u017eil\u00e1ch v\u00a0rudn\u00fdch poloh\u00e1ch odhalen\u00fdch po\u010das \u0165a\u017eby r\u00fad. N\u00e1js\u0165 ich m\u00f4\u017eeme aj vo v\u00e1pencov\u00fdch sediment\u00e1rnych hornin\u00e1ch, napr\u00edklad v\u00a0dutin\u00e1ch stien kame\u0148olomov, b\u00fdvaj\u00fa aj be\u017enou s\u00fa\u010das\u0165ou jask\u00fd\u0148. Kalcit sa vyskytuje tie\u017e\u00a0v\u00a0metamorfovan\u00fdch hornin\u00e1ch ako mramor, \u010do je metamorfovan\u00fd v\u00e1penec, zrnit\u00e1 hornina zlo\u017een\u00e1 z\u00a0kry\u0161talick\u00fdch z\u0155n opisovan\u00e9ho miner\u00e1lu. Kalcitu je podobn\u00fd aj miner\u00e1l aragonit. Maj\u00fa rovnak\u00fd chemick\u00fd vzorec CaCO3, ale ich at\u00f3my s\u00fa ulo\u017een\u00e9 v\u00a0r\u00f4znych konfigur\u00e1ci\u00e1ch. Niektor\u00e9 kry\u0161t\u00e1ly s\u00fa obrovsk\u00e9. Najv\u00e4\u010d\u0161\u00ed jednotliv\u00fd kry\u0161t\u00e1l kalcitu, ak\u00fd sa kedy na\u0161iel, objavili na Islande. Jeho hmotnos\u0165 bola 280 ton.<\/p>\n
Text: Mgr. Andrea Slan\u00e1, PhD.<\/p>\n
<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Zbierkov\u00fdm predmetom mesiaca okt\u00f3ber je miner\u00e1l kalcit z\u00a0geologickej zbierky Pova\u017esk\u00e9ho m\u00fazea. Zemsk\u00e1 k\u00f4ra sa sklad\u00e1 z\u00a0r\u00f4znych horn\u00edn. V\u00e4\u010d\u0161inou s\u00fa to anorganick\u00e9 zl\u00fa\u010deniny zlo\u017een\u00e9 z\u00a0viacer\u00fdch prvkov. Zn\u00e1mych je pribli\u017ene 50 druhov miner\u00e1lov, ktor\u00e9 sa v\u00a0podstatnej miere podie\u013eaj\u00fa na stavbe horn\u00edn. Tieto naz\u00fdvame horninotvorn\u00fdmi. Skupinu m\u00e4kk\u00fdch miner\u00e1lov, ktor\u00e9 vznikaj\u00fa zl\u00fa\u010den\u00edm kovov\u00fdch prvkov s\u00a0uhl\u00edkom a\u00a0kysl\u00edkom, ozna\u010dujeme ako uhli\u010ditany. […]<\/p>\n","protected":false},"author":2,"featured_media":53124,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[31],"tags":[],"class_list":["post-53122","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-aktuality"],"yoast_head":"\n