{"id":5629,"date":"2024-12-04T22:01:14","date_gmt":"2024-12-04T20:01:14","guid":{"rendered":"http:\/\/www.e-gems.cz\/?post_type=kamen&#038;p=5629"},"modified":"2025-03-23T00:02:24","modified_gmt":"2025-03-22T22:02:24","slug":"fenakit","status":"publish","type":"kamen","link":"https:\/\/www.e-gems.cz\/en\/kamen\/fenakit\/","title":{"rendered":"Fenakit\u00a0"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Historie<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Fenakit byl poprv\u00e9 objeven v roce 1833 na \u00fazem\u00ed dne\u0161n\u00edho Ruska, konkr\u00e9tn\u011b v poho\u0159\u00ed Ural v okol\u00ed dolu Mursinka. Pojmenoval jej v roce 1834 rusk\u00fd mineralog Nils Gustaf Nordenski\u00f6ld podle \u0159eck\u00e9ho slova<em> phenakos<\/em> (<em>\u03c6\u03b5\u03bd\u03b1\u03ba\u03bf\u03c2<\/em>), kter\u00e9 znamen\u00e1 podvodn\u00edk nebo klam. Tento n\u00e1zev odr\u00e1\u017e\u00ed skute\u010dnost, \u017ee fenakit m\u016f\u017ee snadno oklamat zku\u0161en\u00e9 mineralogy a klenotn\u00edky, proto\u017ee jeho vzhled a vlastnosti mohou p\u0159ipom\u00ednat jin\u00e9, hodnotn\u011bj\u0161\u00ed drah\u00e9 kameny, p\u0159edev\u0161\u00edm diamant.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Vlastnosti<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Fenakit m\u00e1 chemick\u00fd vzorec Be\u2082SiO\u2084. Jeho tvrdost dosahuje na Mohsov\u011b stupnici hodnoty 7,5 a\u017e 8 a jeho index lomu sv\u011btla se pohybuje v rozmez\u00ed 1,650\u20131,698. V\u011bt\u0161ina fenakit\u016f je bezbarv\u00e1 a pr\u016fhledn\u00e1, vz\u00e1cn\u011bji se v\u0161ak mohou vyskytovat fenakity s n\u00e1dechem r\u016fzn\u00fdch barev \u2013 sv\u011btle r\u016f\u017eov\u00e9, \u017elut\u00e9, hn\u011bd\u00e9, \u010di dokonce modrav\u00e9. Tyto barevn\u00e9 odr\u016fdy jsou zp\u016fsobeny p\u0159\u00edtomnost\u00ed stopov\u00fdch prvk\u016f nebo inkluzemi. Fenakit vykazuje slab\u00fd pleochroismus (schopnost m\u011bnit barvu podle \u00fahlu dopadaj\u00edc\u00edho sv\u011btla) a tato vlastnost je z\u0159eteln\u011bj\u0161\u00ed u barevn\u00fdch variant fenakitu.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Geneze<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Fenakit vznik\u00e1 v pegmatitov\u00fdch \u017eil\u00e1ch v oblasti kontakt\u016f mezi metamorfovan\u00fdmi horninami a intruzivn\u00edmi magmatick\u00fdmi t\u011blesy. \u010casto se nach\u00e1z\u00ed spole\u010dn\u011b s berylem (z n\u011bho\u017e vznik\u00e1 d\u00edky p\u0159\u00edtomnosti berylnat\u00fdch slo\u017eek), k\u0159emenem, topazem a dal\u0161\u00edmi miner\u00e1ly. Pegmatity jsou bohat\u00e9 na vz\u00e1cn\u00e9 prvky, kter\u00e9 umo\u017e\u0148uj\u00ed vznik miner\u00e1l\u016f, jako je fenakit, a vytv\u00e1\u0159\u00ed krystaly hexagon\u00e1ln\u00edho tvaru, kter\u00e9 jsou \u010dasto velmi dob\u0159e vyvinut\u00e9.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">V\u00fdskyt<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Fenakit je relativn\u011b vz\u00e1cn\u00fd miner\u00e1l, a proto jsou i jeho nalezi\u0161t\u011b omezen\u00e1. Historicky prvn\u00ed a nejv\u00fdznamn\u011bj\u0161\u00ed nalezi\u0161t\u011b bylo objeveno na Urale v Rusku, kde byly nalezeny kr\u00e1sn\u00e9 a \u010dist\u00e9 krystaly. Poho\u0159\u00ed Ural z\u016fst\u00e1v\u00e1 dodnes jeho d\u016fle\u017eit\u00fdm zdrojem. Fenakit se d\u00e1le nach\u00e1z\u00ed v oblasti Minas Gerais, kde se t\u011b\u017e\u00ed spolu s jin\u00fdmi drah\u00fdmi kameny, jako je topaz a beryl. Braz\u00edlie je dnes takt\u00e9\u017e jedn\u00edm z hlavn\u00edch sv\u011btov\u00fdch producent\u016f fenakitu. I Madagaskar je zn\u00e1m\u00fd pro sv\u00e9 bohat\u00e9 z\u00e1soby v\u011bt\u0161iny drah\u00fdch kamen\u016f v\u010detn\u011b fenakitu, p\u0159i\u010dem\u017e madagaskarsk\u00fd fenakit je obvykle velmi \u010dist\u00fd a pr\u016fhledn\u00fd. Fenakit byl nalezen i v n\u011bkolika pegmatitov\u00fdch oblastech v&nbsp;Myanmaru (oblast Mogoku).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Imitace<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Fenakit se b\u011b\u017en\u011b ni\u010d\u00edm neimituje, ob\u010das v\u0161ak m\u016f\u017ee b\u00fdt zam\u011bn\u011bn nap\u0159. za danburit a jin\u00e9 bezbarv\u00e9 drah\u00e9 kameny.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Syntetick\u00e1 v\u00fdroba<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Synteticky se nevyr\u00e1b\u00ed, p\u0159esto\u017ee je jeho syntetick\u00e1 v\u00fdroba zn\u00e1ma.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Historie Fenakit byl poprv\u00e9 objeven v roce 1833 na \u00fazem\u00ed dne\u0161n\u00edho Ruska, konkr\u00e9tn\u011b v poho\u0159\u00ed Ural v okol\u00ed dolu Mursinka. Pojmenoval jej v roce 1834 rusk\u00fd mineralog Nils Gustaf Nordenski\u00f6ld podle \u0159eck\u00e9ho slova phenakos (\u03c6\u03b5\u03bd\u03b1\u03ba\u03bf\u03c2), kter\u00e9 znamen\u00e1 podvodn\u00edk nebo klam. Tento n\u00e1zev odr\u00e1\u017e\u00ed skute\u010dnost, \u017ee fenakit m\u016f\u017ee snadno oklamat zku\u0161en\u00e9 mineralogy a klenotn\u00edky, proto\u017ee jeho [&hellip;]<\/p>\n","protected":false},"featured_media":7692,"template":"","meta":{"_acf_changed":false,"inline_featured_image":false},"class_list":["post-5629","kamen","type-kamen","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.e-gems.cz\/en\/wp-json\/wp\/v2\/kamen\/5629","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.e-gems.cz\/en\/wp-json\/wp\/v2\/kamen"}],"about":[{"href":"https:\/\/www.e-gems.cz\/en\/wp-json\/wp\/v2\/types\/kamen"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.e-gems.cz\/en\/wp-json\/wp\/v2\/media\/7692"}],"wp:attachment":[{"href":"https:\/\/www.e-gems.cz\/en\/wp-json\/wp\/v2\/media?parent=5629"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}