{"product_id":"frosted-amethyst-geode-sculptural-volcanic-formation-brazil","title":"Frosted Amethyst Geode | Sculptural Volcanic Formation | Brazil","description":"\u003cp data-start=\"556\" data-end=\"590\"\u003eLikely Rio Grande do Sul, Brazil\u003c\/p\u003e\n\u003cp data-start=\"592\" data-end=\"750\"\u003e\u003cstrong data-start=\"592\" data-end=\"603\"\u003eWeight:\u003c\/strong\u003e 1.224 kg\u003cbr data-start=\"612\" data-end=\"615\"\u003e\u003cstrong data-start=\"615\" data-end=\"624\"\u003eSize:\u003c\/strong\u003e approx. 12 × 13 × 7–8 cm\u003cbr data-start=\"649\" data-end=\"652\"\u003e\u003cstrong data-start=\"652\" data-end=\"667\"\u003eBase width:\u003c\/strong\u003e approx. 8 cm\u003cbr data-start=\"680\" data-end=\"683\"\u003e\u003cstrong data-start=\"683\" data-end=\"702\"\u003eStand included:\u003c\/strong\u003e No\u003cbr data-start=\"705\" data-end=\"708\"\u003e\u003cstrong data-start=\"708\" data-end=\"724\"\u003eUV response:\u003c\/strong\u003e No notable fluorescence\u003c\/p\u003e\n\u003cp data-start=\"757\" data-end=\"783\"\u003e\u003cstrong data-start=\"760\" data-end=\"783\"\u003eAbout this specimen\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"785\" data-end=\"937\"\u003eThis is a substantial, naturally bowl-shaped amethyst geode with densely packed quartz crystal growth and a distinctive matte “frosted” surface texture.\u003c\/p\u003e\n\u003cp data-start=\"939\" data-end=\"1247\"\u003eIn daylight, the piece displays soft lilac outer crystals transitioning into deeper violet tones toward the centre of the cavity. The crystal faces are coated in a fine micro-druzy overgrowth, creating a velvety, sugared appearance rather than the high-gloss finish often seen in commercial cathedral pieces.\u003c\/p\u003e\n\u003cp data-start=\"1249\" data-end=\"1472\"\u003eThe thick agate rind and rounded cavity form are consistent with basalt-hosted volcanic geodes. The bowl-like structure gives the specimen depth and strong natural symmetry, making it visually striking from multiple angles.\u003c\/p\u003e\n\u003cp data-start=\"1474\" data-end=\"1573\"\u003eMinor edge chips are present from extraction — these are natural mining marks and not later damage.\u003c\/p\u003e\n\u003chr data-start=\"1575\" data-end=\"1578\"\u003e\n\u003cp data-start=\"1580\" data-end=\"1607\"\u003e \u003cstrong data-start=\"1583\" data-end=\"1607\"\u003eGeological formation\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"1609\" data-end=\"1681\"\u003eThis geode formed within a gas cavity inside a cooling basalt lava flow.\u003c\/p\u003e\n\u003cp data-start=\"1683\" data-end=\"1893\"\u003eAs the volcanic rock solidified, hollow pockets were left behind. Over time, silica-rich hydrothermal fluids moved through fractures in the basalt, depositing successive layers of quartz along the cavity walls.\u003c\/p\u003e\n\u003cp data-start=\"1895\" data-end=\"2102\"\u003eTrace amounts of iron became incorporated into the quartz lattice during crystallisation. Natural irradiation later altered the iron’s oxidation state, producing the purple colour characteristic of amethyst.\u003c\/p\u003e\n\u003cp data-start=\"2104\" data-end=\"2336\"\u003eThe frosted texture seen on this specimen likely developed during a later stage of mineral growth, when subtle shifts in fluid chemistry caused micro-crystalline quartz to overgrow the existing crystal faces, softening their lustre.\u003c\/p\u003e\n\u003chr data-start=\"2338\" data-end=\"2341\"\u003e\n\u003cp data-start=\"2343\" data-end=\"2375\"\u003e\u003cstrong data-start=\"2345\" data-end=\"2375\"\u003eApproximate geological age\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"2377\" data-end=\"2473\"\u003eAmethyst geodes from southern Brazil are typically associated with the Paraná volcanic province.\u003c\/p\u003e\n\u003cp data-start=\"2475\" data-end=\"2516\"\u003eThese basalt flows date to approximately:\u003c\/p\u003e\n\u003cp data-start=\"2518\" data-end=\"2575\"\u003e\u003cstrong data-start=\"2518\" data-end=\"2547\"\u003e130–135 million years old\u003c\/strong\u003e\u003cbr data-start=\"2547\" data-end=\"2550\"\u003e(Early Cretaceous period)\u003c\/p\u003e\n\u003cp data-start=\"2577\" data-end=\"2668\"\u003eThis means the cavity that now holds these crystals formed during the age of the dinosaurs.\u003c\/p\u003e\n\u003chr data-start=\"2670\" data-end=\"2673\"\u003e\n\u003cp data-start=\"2675\" data-end=\"2704\"\u003e \u003cstrong data-start=\"2677\" data-end=\"2704\"\u003eRarity \u0026amp; collectability\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"2706\" data-end=\"2753\"\u003eWhile amethyst itself is not rare, pieces with:\u003c\/p\u003e\n\u003cul data-start=\"2755\" data-end=\"2972\"\u003e\n\u003cli data-start=\"2755\" data-end=\"2795\"\u003e\n\u003cp data-start=\"2757\" data-end=\"2795\"\u003eNatural bowl-shaped cavity formation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2796\" data-end=\"2823\"\u003e\n\u003cp data-start=\"2798\" data-end=\"2823\"\u003eThick intact agate rind\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2824\" data-end=\"2858\"\u003e\n\u003cp data-start=\"2826\" data-end=\"2858\"\u003eEven internal crystal coverage\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2859\" data-end=\"2898\"\u003e\n\u003cp data-start=\"2861\" data-end=\"2898\"\u003eDistinct matte “frosted” overgrowth\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2899\" data-end=\"2935\"\u003e\n\u003cp data-start=\"2901\" data-end=\"2935\"\u003eStrong central violet saturation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2936\" data-end=\"2972\"\u003e\n\u003cp data-start=\"2938\" data-end=\"2972\"\u003eSubstantial weight (over 1.2 kg)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2974\" data-end=\"3035\"\u003eare less commonly seen than standard polished cathedral cuts.\u003c\/p\u003e\n\u003cp data-start=\"3037\" data-end=\"3211\"\u003eThe frosted surface gives this specimen a more geological, unrefined character — preserving the natural growth history rather than presenting a polished commercial aesthetic.\u003c\/p\u003e\n\u003cp data-start=\"3213\" data-end=\"3260\"\u003eThis is a strong display specimen suitable for:\u003c\/p\u003e\n\u003cul data-start=\"3262\" data-end=\"3357\"\u003e\n\u003cli data-start=\"3262\" data-end=\"3286\"\u003e\n\u003cp data-start=\"3264\" data-end=\"3286\"\u003eA cabinet collection\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"3287\" data-end=\"3314\"\u003e\n\u003cp data-start=\"3289\" data-end=\"3314\"\u003eA statement shelf piece\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"3315\" data-end=\"3357\"\u003e\n\u003cp data-start=\"3317\" data-end=\"3357\"\u003eA natural-formation focused collection\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"3359\" data-end=\"3362\"\u003e\n\u003cp data-start=\"3364\" data-end=\"3386\"\u003e\u003cstrong data-start=\"3367\" data-end=\"3386\"\u003eCare \u0026amp; handling\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"3388\" data-end=\"3543\"\u003eHandle with care — natural crystal points are delicate\u003cbr data-start=\"3442\" data-end=\"3445\"\u003eAvoid prolonged moisture exposure\u003cbr data-start=\"3478\" data-end=\"3481\"\u003eDisplay away from strong, direct sunlight to preserve colour\u003c\/p\u003e","brand":"Starshine Minerals","offers":[{"title":"Default Title","offer_id":56746890002776,"sku":null,"price":295.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0969\/4304\/7000\/files\/IMG_8369.jpg?v=1771444613","url":"https:\/\/starshineminerals.co.uk\/products\/frosted-amethyst-geode-sculptural-volcanic-formation-brazil","provider":"Starshine Minerals","version":"1.0","type":"link"}