{"product_id":"goethite-bilbao-biscay-basque-country-spain-copy","title":"Optical Calcite (Iceland Spar)- California, USA","description":"\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOptical Calcite (Iceland Spar)\u003c\/span\u003e\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003eCalifornia, USA\u003c\/span\u003e\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003eDimensions:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 3.5 × 2.5 × 1.5 cm\u003c\/span\u003e\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003eProvenance:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Original vintage collection label, catalog no. 151, included with specimen. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA beautiful, transparent to translucent specimen of optical Calcite, commonly known as Iceland Spar, displaying a nearly colorless appearance with subtle champagne undertones. The specimen features broad, naturally reflective cleavage faces and distinctive rhombohedral geometry, with internal fractures and fine linear features creating delicate flashes of light.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIceland Spar is a particularly transparent variety of Calcite (CaCO₃), celebrated for its remarkable optical properties. It exhibits strong double refraction, also known as birefringence, which causes objects viewed through the crystal to appear doubled. Historically important in the study of optics and polarization, Iceland Spar remains a fascinating mineral for collectors and enthusiasts of crystallography. This vintage California specimen combines attractive transparency, well-defined cleavage, and original collection provenance.\u003c\/span\u003e\u003c\/p\u003e","brand":"The Crystalary","offers":[{"title":"Default Title","offer_id":67977207545987,"sku":"barrydwr5-1of2-151","price":20.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0390\/4634\/8931\/files\/IMG_37472.jpg?v=1792521315","url":"https:\/\/www.thecrystalary.com\/products\/goethite-bilbao-biscay-basque-country-spain-copy","provider":"The Crystalary","version":"1.0","type":"link"}