{"title":"Opal","description":"\u003cp\u003e\u003cstrong\u003eOpal\u003c\/strong\u003e is a hydrated form of amorphous silica (SiO₂·nH₂O) prized as one of the most captivating gemstones ever offered to collectors. Classified as a mineraloid rather than a true crystalline mineral, its water content typically ranges between 3% and 21% by weight. What sets fine specimens apart is \u003cstrong\u003eplay-of-color\u003c\/strong\u003e, the shimmering flash of spectral hues caused by light diffracting through a regular lattice of microscopic silica spheres — a phenomenon absent in ordinary \u003cstrong\u003ecommon opal\u003c\/strong\u003e. Collectors distinguish numerous varieties, including \u003cstrong\u003eblack opal\u003c\/strong\u003e, \u003cstrong\u003ewhite opal\u003c\/strong\u003e, \u003cstrong\u003ecrystal opal\u003c\/strong\u003e, \u003cstrong\u003eboulder opal\u003c\/strong\u003e, \u003cstrong\u003efire opal\u003c\/strong\u003e, \u003cstrong\u003ejelly opal\u003c\/strong\u003e, \u003cstrong\u003ematrix opal\u003c\/strong\u003e, and the botryoidal, colorless \u003cstrong\u003ehyalite\u003c\/strong\u003e, alongside pseudomorphs after wood, shell, and even the rare mineral ikaite, as seen in the famous \u003cstrong\u003epineapple opal\u003c\/strong\u003e of White Cliffs.\u003c\/p\u003e\u003cp\u003eAustralia dominates the world's precious opal output, and its fields read like a collector's map: \u003cstrong\u003eLightning Ridge\u003c\/strong\u003e in New South Wales for the legendary black opal with vivid reds and greens set against a dark body tone; \u003cstrong\u003eCoober Pedy\u003c\/strong\u003e in South Australia for luminous white and crystal opal mined from underground workings; \u003cstrong\u003eWhite Cliffs\u003c\/strong\u003e for early precious seam opal and opalized fossils; and the Queensland fields of \u003cstrong\u003eYowah\u003c\/strong\u003e and \u003cstrong\u003eKoroit\u003c\/strong\u003e, source of nearly all the world's ironstone-hosted \u003cstrong\u003eboulder opal\u003c\/strong\u003e. Beyond Australia, Ethiopia's \u003cstrong\u003eWollo Province\u003c\/strong\u003e, near Wegel Tena, has become a major source of hydrophane precious opal since large deposits were confirmed in 2008, prized for bright honeycomb and broad-flash color patterns; the older \u003cstrong\u003eShewa Province\u003c\/strong\u003e deposits, discovered in 1994 in the Menz Gishe District, remain historically important. Mexico, particularly Querétaro, is renowned for transparent \u003cstrong\u003efire opal\u003c\/strong\u003e in glowing orange and red, while Nevada's \u003cstrong\u003eVirgin Valley\u003c\/strong\u003e yields spectacular, if fragile, opalized wood and black opal. Brazil's \u003cstrong\u003eMinas Gerais\u003c\/strong\u003e, Honduras, Indonesia, Slovakia's historic Červenica deposits — the primary ancient source before Australia's discovery — and Peru's Ica and Caraveli provinces for prized pink opal round out the global picture.\u003c\/p\u003e\u003cp\u003eFor mineral collectors, opal is valued not only as a gem but as a mineralogical curiosity: an amorphous solid capable of pseudomorphing calcite, feldspar, and fossil organic matter, and one of the few materials whose internal structure — close-packed silica nanospheres just 150–300 nanometers across — can be directly linked to its optical brilliance. Rarity drives desirability: black opal from Lightning Ridge and vivid Welo material from Ethiopia are especially sought after, while matrix, boulder, and hyalite specimens appeal to those who collect opal in its natural geological context rather than as cut gemstones.\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\/opal.oembed","provider":"ITALMINERAL","version":"1.0","type":"link"}