{"title":"Hyalite","description":"\u003cp\u003e\u003cstrong\u003eHyalite\u003c\/strong\u003e is a colorless, glassy variety of common opal (Opal-AN), an amorphous hydrous silica prized for its clear, jelly-like botryoidal and globular crusts rather than any play-of-color. Unlike precious opal, hyalite lacks internal diffraction structure, but many specimens compensate with a striking party trick: a bright green fluorescence under both shortwave and longwave UV, and in the finest material even a visible daylight glow. This luminescence comes from trace amounts of the uranyl (UO2)2+ molecule locked into the silica gel as it deposited from volcanic or pegmatitic vapors, giving hyalite a devoted following among fluorescent mineral collectors alongside classics like autunite and adamite.\u003c\/p\u003e\u003cp\u003eHistorically the type material comes from the volcanic clefts of \u003cstrong\u003eValeč\u003c\/strong\u003e in the Karlovy Vary Region of the \u003cstrong\u003eCzech Republic\u003c\/strong\u003e, a locality so significant that hyalite from trachytic rocks there and in the \u003cstrong\u003eAuvergne\u003c\/strong\u003e region of France defined the variety for 19th-century mineralogists. Classic European hyalite is also documented from \u003cstrong\u003eHungary\u003c\/strong\u003e and from pegmatite pockets such as the \u003cstrong\u003eNaegi granite\u003c\/strong\u003e in Gifu, Japan, and hot-spring deposits at Toyama's \u003cstrong\u003eShin-yu\u003c\/strong\u003e locality. Additional occurrences are known from \u003cstrong\u003eOregon\u003c\/strong\u003e and \u003cstrong\u003eUtah\u003c\/strong\u003e in the United States, from \u003cstrong\u003eArarat\u003c\/strong\u003e in Turkey, and from widespread but poorly documented finds across Argentina.\u003c\/p\u003e\u003cp\u003eThe specimens that revolutionized the hyalite market, however, came from \u003cstrong\u003eZacatecas\u003c\/strong\u003e, Mexico, first found around 2013 at the so-called Electric Opal claim. This Mexican hyalite shows an intensely bright yellow-green glow under UV and, remarkably, a visible green fluorescence in ordinary shaded daylight — a phenomenon almost unmatched among fluorescent minerals and shared by only a handful of other deposits, notably in the Erongo region of Namibia. Trace uranium content makes these pieces mildly radioactive, though at levels well below any health concern. Because true daylight-fluorescent hyalite is genuinely scarce on the specimen market, well-formed botryoidal clusters with strong green response — whether from Zacatecas, Erongo, or the historic Czech and Hungarian deposits — remain highly sought after by opal specialists, UV-mineral collectors, and anyone assembling a representative silica-mineral suite.\u003c\/p\u003e","products":[{"product_id":"fa16-hyalite-sardegna-0","title":"HYALITE OPAL – Extremely Rare Yellow Coralloid Crystals, Santa Lucia Mine, Sardinia, Italy","description":"\u003cp\u003eA rare and visually striking specimen of yellow and white Hyalite Opal displaying a distinctive coralloid (globular, coral-like) crystallization, recovered from the historic Santa Lucia Mine near Fluminimaggiore, Sardinia. The unusual yellow tone and the rounded, glassy botryoidal surface make this a standout piece for both aesthetic display and species collecting.\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 33 x 27 x 18 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 20 g\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProvenance:\u003c\/strong\u003e Santa Lucia Mine, Fluminimaggiore, Sardinia, Italy\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ITALMINERAL","offers":[{"title":"Default Title","offer_id":45460096548973,"sku":null,"price":69.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0693\/8027\/6333\/files\/IMG20260421215033.jpg?v=1784129907"}],"url":"https:\/\/www.italmineral.com\/collections\/hyalite.oembed","provider":"ITALMINERAL","version":"1.0","type":"link"}