{"title":"Calcite ottica","description":"\u003cp data-start=\"0\" data-end=\"316\"\u003eLa \u003cstrong data-start=\"3\" data-end=\"22\"\u003ecalcite ottica\u003c\/strong\u003e, nota anche \u003cstrong data-start=\"38\" data-end=\"57\"\u003espato islandese\u003c\/strong\u003e, è una varietà trasparente e pura di calcite (carbonato di calcio, CaCO₃). È celebre per le sue \u003cstrong data-start=\"164\" data-end=\"203\"\u003eeccezionali proprietà ottiche\u003c\/strong\u003e, in particolare per il \u003cstrong data-start=\"218\" data-end=\"248\"\u003efenomeno della birifrangenza\u003c\/strong\u003e, che la rende un materiale molto utilizzato in ottica e in mineralogia.\u003c\/p\u003e\n\u003chr data-start=\"318\" data-end=\"321\"\u003e\n\u003ch3 data-start=\"323\" data-end=\"358\"\u003e🌟 Caratteristiche principali\u003c\/h3\u003e\n\u003cul data-start=\"360\" data-end=\"736\"\u003e\n\n\u003cli data-start=\"360\" data-end=\"392\"\u003e\n\n\u003cp data-start=\"362\" data-end=\"392\"\u003e\u003cstrong data-start=\"362\" data-end=\"382\"\u003eFormula chimica\u003c\/strong\u003e: CaCO₃\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"393\" data-end=\"445\"\u003e\n\n\u003cp data-start=\"395\" data-end=\"445\"\u003e\u003cstrong data-start=\"395\" data-end=\"417\"\u003eSistema cristallino\u003c\/strong\u003e: romboedrico (trigonale)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"446\" data-end=\"480\"\u003e\n\n\u003cp data-start=\"448\" data-end=\"480\"\u003e\u003cstrong data-start=\"448\" data-end=\"476\"\u003eDurezza (scala di Mohs)\u003c\/strong\u003e: 3\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"481\" data-end=\"543\"\u003e\n\n\u003cp data-start=\"483\" data-end=\"543\"\u003e\u003cstrong data-start=\"483\" data-end=\"494\"\u003eClivaggio\u003c\/strong\u003e: perfetto secondo tre direzioni (romboedrico)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"544\" data-end=\"643\"\u003e\n\n\u003cp data-start=\"546\" data-end=\"643\"\u003e\u003cstrong data-start=\"546\" data-end=\"557\"\u003eColore\u003c\/strong\u003e: incolore o bianco nella sua forma pura (la calcite ottica è generalmente limpida)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"644\" data-end=\"691\"\u003e\n\n\u003cp data-start=\"646\" data-end=\"691\"\u003e\u003cstrong data-start=\"646\" data-end=\"662\"\u003eTrasparenza\u003c\/strong\u003e: da trasparente a traslucida\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"692\" data-end=\"736\"\u003e\n\n\u003cp data-start=\"694\" data-end=\"736\"\u003e\u003cstrong data-start=\"694\" data-end=\"711\"\u003eBirifrangenza\u003c\/strong\u003e: molto forte (δ ≈ 0,172)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003chr data-start=\"738\" data-end=\"741\"\u003e\n\u003ch3 data-start=\"743\" data-end=\"776\"\u003e🔍 Fenomeno della birifrangenza\u003c\/h3\u003e\n\u003cp data-start=\"778\" data-end=\"872\"\u003eLa calcite ottica è \u003cstrong data-start=\"801\" data-end=\"847\"\u003euno dei migliori esempi di birifrangenza\u003c\/strong\u003e (o doppia rifrazione):\u003c\/p\u003e\n\u003cul data-start=\"874\" data-end=\"1112\"\u003e\n\n\u003cli data-start=\"874\" data-end=\"1016\"\u003e\n\n\u003cp data-start=\"876\" data-end=\"1016\"\u003eQuando un raggio luminoso entra nel cristallo, viene \u003cstrong data-start=\"931\" data-end=\"969\"\u003escomposto in due raggi polarizzati\u003c\/strong\u003e che seguono percorsi leggermente diversi.\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1017\" data-end=\"1112\"\u003e\n\n\u003cp data-start=\"1019\" data-end=\"1112\"\u003eOsservando un oggetto attraverso un cristallo di calcite ottica, si vede \u003cstrong data-start=\"1090\" data-end=\"1111\"\u003eun'immagine doppia\u003c\/strong\u003e.\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp data-start=\"1114\" data-end=\"1269\"\u003eQuesto fenomeno è dovuto alla struttura cristallina anisotropa della calcite, che fa sì che la luce si propaghi a velocità diverse a seconda della direzione.\u003c\/p\u003e\n\u003chr data-start=\"1271\" data-end=\"1274\"\u003e\n\u003ch3 data-start=\"1276\" data-end=\"1295\"\u003e🧪 Applicazioni\u003c\/h3\u003e\n\u003cul data-start=\"1297\" data-end=\"1495\"\u003e\n\n\u003cli data-start=\"1297\" data-end=\"1367\"\u003e\n\n\u003cp data-start=\"1299\" data-end=\"1367\"\u003e\u003cstrong data-start=\"1299\" data-end=\"1334\"\u003ePrismi e polarizzatori ottici\u003c\/strong\u003e (come i polarizzatori di Nicol)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1368\" data-end=\"1407\"\u003e\n\n\u003cp data-start=\"1370\" data-end=\"1407\"\u003e\u003cstrong data-start=\"1370\" data-end=\"1407\"\u003eStudi in microscopia polarizzata\u003c\/strong\u003e\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1408\" data-end=\"1451\"\u003e\n\n\u003cp data-start=\"1410\" data-end=\"1451\"\u003e\u003cstrong data-start=\"1410\" data-end=\"1451\"\u003eEsperimenti di fisica della luce\u003c\/strong\u003e\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1452\" data-end=\"1495\"\u003e\n\n\u003cp data-start=\"1454\" data-end=\"1495\"\u003e\u003cstrong data-start=\"1454\" data-end=\"1478\"\u003eOggetti da collezione\u003c\/strong\u003e (in mineralogia)\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003chr data-start=\"1497\" data-end=\"1500\"\u003e\n\u003ch3 data-start=\"1502\" data-end=\"1529\"\u003e📍 Origine e giacimenti\u003c\/h3\u003e\n\u003cp data-start=\"1531\" data-end=\"1626\"\u003eLo spato islandese deve il suo nome all'abbondanza in \u003cstrong data-start=\"1583\" data-end=\"1594\"\u003eIslanda\u003c\/strong\u003e, ma si trova anche in:\u003c\/p\u003e\n\u003cul data-start=\"1627\" data-end=\"1680\"\u003e\n\n\u003cli data-start=\"1627\" data-end=\"1639\"\u003e\n\n\u003cp data-start=\"1629\" data-end=\"1639\"\u003eMessico\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1640\" data-end=\"1656\"\u003e\n\n\u003cp data-start=\"1642\" data-end=\"1656\"\u003eStati Uniti\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1657\" data-end=\"1667\"\u003e\n\n\u003cp data-start=\"1659\" data-end=\"1667\"\u003eCina\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1668\" data-end=\"1680\"\u003e\n\n\u003cp data-start=\"1670\" data-end=\"1680\"\u003eNorvegia\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp data-start=\"1682\" data-end=\"1803\"\u003eI cristalli più apprezzati sono limpidi, privi di inclusioni e tagliati con angoli precisi per usi ottici.\u003c\/p\u003e\n\u003chr data-start=\"1805\" data-end=\"1808\"\u003e\n\u003ch3 data-start=\"1810\" data-end=\"1834\"\u003e✨ Curiosità\u003c\/h3\u003e\n\u003cul data-start=\"1836\" data-end=\"2036\"\u003e\n\n\u003cli data-start=\"1836\" data-end=\"1936\"\u003e\n\n\u003cp data-start=\"1838\" data-end=\"1936\"\u003eIsaac Newton e altri pionieri dell'ottica studiarono la calcite ottica fin dal XVII secolo.\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1937\" data-end=\"2036\"\u003e\n\n\u003cp data-start=\"1939\" data-end=\"2036\"\u003eÈ un esempio perfetto di minerale anisotropo nei corsi di mineralogia e cristallografia.\u003c\/p\u003e\n\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e","products":[{"product_id":"spath-dislande-calcite-optique-bresil-a-1","title":"Spato d'Islanda (Calcite ottica) Brasile A","description":"\u003cp\u003eSPATH-B-01\u003cbr\u003eOrigine: Brasile\u003cbr\u003eGrado: A\u003c\/p\u003e\n\u003cp\u003e \u003cbr\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cspan class=\"PBMainTxt\"\u003eDimensioni:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eCirca 20-30mm\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr class=\"PBMainTxt\"\u003e\u003cspan class=\"PBMainTxt\"\u003ePeso:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eTra 10 e 20g\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan class=\"PBMainTxt\"\u003eOrigine:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eBrasile (PANTANAL)\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan class=\"PBMainTxt\"\u003eGrado:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eA = buono\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eSpato d'Islanda (calcite ottica) dal Brasile di circa 20-30mm\u003cbr\u003eVenduta singolarmente.\u003cbr\u003e\u003cstrong\u003eI colori e le forme possono variare da una pietra all'altra\u003c\/strong\u003e\u003cbr\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"font-family: Arial, Helvetica, sans-serif; box-sizing: border-box;\"\u003e\u003cspan style=\"color: rgb(226, 101, 0); font-family: 'Fjalla One', sans-serif; font-size: 16px;\"\u003e\u003cspan style=\"box-sizing: border-box; font-family: arial, sans-serif; color: rgb(45, 34, 50); font-size: 14px;\"\u003eScopri le caratteristiche della pietra nella nostra sezione dedicata qui: \u003c\/span\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.laboiteacailloux.com\/collections\/calcite-optique\"\u003e\u003cspan\u003e\u003cspan style=\"color: rgb(226, 101, 0); font-family: 'Fjalla One', sans-serif; font-size: 16px;\"\u003e\u003cspan style=\"box-sizing: border-box; font-family: arial, sans-serif; color: rgb(45, 34, 50); font-size: 14px;\"\u003ehttps:\/\/www.laboiteacailloux.com\/collections\/calcite-optique\u003c\/span\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"La Boite à Cailloux","offers":[{"title":"Default Title","offer_id":48990193975644,"sku":"SPATH-B-01","price":3.9,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0808\/8577\/6732\/files\/spath-dislande-calcite-optique-bresil-a-5907927.jpg?v=1779713716"},{"product_id":"copie-spath-dislande-calcite-optique-bresil-a","title":"Ciondolo in calcite ottica grezza (Spat d'Islanda) Brasile AA","description":"\u003cp\u003ePEN-CALCOPT-01\u003cbr\u003eOrigine: Brasile\u003cbr\u003eGrado: AA\u003c\/p\u003e\n\u003cp\u003e \u003cbr\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cspan class=\"PBMainTxt\"\u003eDimensioni:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eCirca 20-30mm\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr class=\"PBMainTxt\"\u003e\u003cspan class=\"PBMainTxt\"\u003ePeso:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eTra 3 e 5g\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan class=\"PBMainTxt\"\u003eOrigine:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eBrasile (PANTANAL)\u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan class=\"PBMainTxt\"\u003eGrado:\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003eAA = molto elevato \u003c\/span\u003e\u003cspan class=\"PBMainTxt\" style=\"box-sizing: border-box;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eCiondolo composto da una calcite ottica grezza (Spat d'Islanda) del Brasile di circa 20-30mm\u003cbr\u003eVenduto singolarmente.\u003cbr\u003e\u003cstrong\u003eI colori e le forme possono variare da una pietra all'altra\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cdiv style=\"font-family: Arial, Helvetica, sans-serif; box-sizing: border-box;\"\u003e\u003cspan style=\"color: rgb(226, 101, 0); font-family: 'Fjalla One', sans-serif; font-size: 16px;\"\u003e\u003cspan style=\"box-sizing: border-box; font-family: arial, sans-serif; color: rgb(45, 34, 50); font-size: 14px;\"\u003eScopri le caratteristiche della pietra nella nostra rubrica dedicata qui: \u003c\/span\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.laboiteacailloux.com\/collections\/calcite-optique\"\u003e\u003cspan\u003e\u003cspan style=\"color: rgb(226, 101, 0); font-family: 'Fjalla One', sans-serif; font-size: 16px;\"\u003e\u003cspan style=\"box-sizing: border-box; font-family: arial, sans-serif; color: rgb(45, 34, 50); font-size: 14px;\"\u003ehttps:\/\/www.laboiteacailloux.com\/collections\/calcite-optique\u003c\/span\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"La Boite à Cailloux","offers":[{"title":"Default Title","offer_id":54066870190428,"sku":"PEN-CALCOPT-01","price":5.9,"currency_code":"EUR","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0808\/8577\/6732\/files\/pendentif-calcite-optique-brute-spath-dislande-bresil-aa-8677268.jpg?v=1779713172"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0808\/8577\/6732\/collections\/calcite-optique-3250443.jpg?v=1779712799","url":"https:\/\/www.laboiteacailloux.com\/it\/collections\/calcite-optique.oembed","provider":"La Boite à Cailloux","version":"1.0","type":"link"}