{"title":"Heulandite","description":"\u003cp\u003eHeulandite is a hydrous calcium-sodium aluminosilicate belonging to the \u003cstrong\u003ezeolite group\u003c\/strong\u003e, prized by collectors for its glassy, pearly-lustered, coffin-shaped or tabular crystals that form radiating and saddle-like clusters. Chemically expressed as (Ca,Na)₂₋₃Al₃(Al,Si)₂Si₁₃O₃₆·12H₂O, it belongs to the \u003cstrong\u003eheulandite subgroup\u003c\/strong\u003e, which also includes heulandite-Na, heulandite-K, heulandite-Ba and heulandite-Sr, alongside the closely related species \u003cstrong\u003estilbite\u003c\/strong\u003e and \u003cstrong\u003eclinoptilolite\u003c\/strong\u003e. With a Mohs hardness of 3.5-4, perfect one-directional cleavage, and a vitreous-to-pearly sheen, heulandite most typically occurs as a secondary mineral lining \u003cstrong\u003eamygdaloidal cavities\u003c\/strong\u003e in basalt and andesite, where slowly cooling volcanic gas pockets provided the open space needed for its distinctive crystals to grow.\u003c\/p\u003e\u003cp\u003eThe type locality tradition and the finest classic material both trace back to the \u003cstrong\u003eDeccan Traps\u003c\/strong\u003e of Maharashtra, India, especially the quarries around \u003cstrong\u003eJalgaon\u003c\/strong\u003e, \u003cstrong\u003eNasik\u003c\/strong\u003e, and \u003cstrong\u003ePune\u003c\/strong\u003e, where basalt geodes yield large, well-formed crystals in pink, peach, orange, salmon, and white, often accompanied by \u003cstrong\u003estilbite\u003c\/strong\u003e and \u003cstrong\u003equartz\u003c\/strong\u003e. In Iceland, exceptional colorless-to-white heulandite has been recovered from classic basaltic terrains such as \u003cstrong\u003eBulandsdalur\u003c\/strong\u003e and \u003cstrong\u003eBerufjörður\u003c\/strong\u003e, while the \u003cstrong\u003eFaroe Islands\u003c\/strong\u003e, \u003cstrong\u003eScotland\u003c\/strong\u003e, and \u003cstrong\u003eSardinia\u003c\/strong\u003e have furnished historically significant European specimens. North America contributes its own noteworthy finds: deep red heulandite with laumontite on quartz from the \u003cstrong\u003eProspect Park Quarry\u003c\/strong\u003e in New Jersey, colorless crystals with thomsonite and celadonite at the \u003cstrong\u003eShine Quarry\u003c\/strong\u003e in Washington State, and further occurrences reported from Nova Scotia, Quebec, Oregon, Idaho, and Colorado. The mineral is named after \u003cstrong\u003eJohn Henry Heuland\u003c\/strong\u003e, the early 19th-century English mineral collector and dealer, honored when the species was described in 1822. Green heulandite colored by celadonite inclusions, along with vivid orange and red varieties, are especially sought after, contrasting beautifully against dark basaltic matrix.\u003c\/p\u003e\u003cp\u003eBeyond its aesthetic and mineralogical appeal, heulandite offers collectors a window into low-grade metamorphic and hydrothermal processes, often marking the transition zone before conversion into denser zeolites like laumontite and albite in deeply buried volcanic sequences. Its porous \u003cstrong\u003etectosilicate\u003c\/strong\u003e framework, capable of housing water and exchangeable cations, also links it to the broader industrial relevance of zeolites in filtration and ion-exchange applications. For specimen collectors, however, it is the combination of striking crystal habit, wide color range, and strong locality character — from Indian basalt geodes to Icelandic lava fields — that keeps heulandite a perennial favorite in zeolite and volcanic-mineral collections.\u003c\/p\u003e","products":[{"product_id":"heulandite-blood-red-crystals-fassa-valley-italy","title":"HEULANDITE – Blood-Red Crystals on matrix, Fassa Valley, Trentino, Italy","description":"\u003cp\u003eThis is a genuine specimen of Heulandite from the historic zeolite deposits of the Fassa Valley, Trentino-Alto Adige, Italy, showing well-formed crystals in a striking blood-red color caused by natural iron oxide inclusions. The crystals are harmoniously distributed across the matrix, creating a pleasing contrast that gives this piece strong aesthetic and mineralogical value.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMineral Data:\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 70 x 70 x 41 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 129 g\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProvenance:\u003c\/strong\u003e Fassa Valley, Trento Province, Trentino-Alto Adige (South Tyrol), Italy\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ITALMINERAL","offers":[{"title":"Default Title","offer_id":45608821620845,"sku":null,"price":15.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0693\/8027\/6333\/files\/IMG20260710185305.jpg?v=1786521265"},{"product_id":"heulandite-pink-crystals-on-matrix-pune-india","title":"HEULANDITE – Lustrous Pink Crystals on Dark matrix, Pune, Maharashtra, India","description":"\u003cp\u003eA striking Heulandite specimen from the Deccan Traps of Maharashtra, India, showcasing a rich cluster of well-formed pink crystals resting on a dark basalt matrix. The tabular, coffin-shaped crystals display a pleasant pearly-vitreous luster and excellent size, creating a beautiful chromatic contrast against the host rock that makes this piece both aesthetically appealing and scientifically interesting.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMineral Data:\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 78 x 50 x 33 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 113 g\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProvenance:\u003c\/strong\u003e Pune District, Pune Division, Maharashtra, India\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ITALMINERAL","offers":[{"title":"Default Title","offer_id":45609660416109,"sku":null,"price":29.0,"currency_code":"EUR","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0693\/8027\/6333\/files\/IMG20260715175848.jpg?v=1786526109"}],"url":"https:\/\/www.italmineral.com\/collections\/heulandite.oembed","provider":"ITALMINERAL","version":"1.0","type":"link"}