CAVANSITE ON STILBITE
ABOUT THE SPECIMEN
Electric blue cavansite formed in a long cluster wrapping around a protrusion of stilbite covered host rock. The cavansite shoots outwards in all directions, and at the end of the grouping sits a spherical growth, the kind the species is known for. Looking into small pockets, one can see that the cavansite growth continues deeper out of sight. It's highly uncommon to find this much of it together in one continuous grouping, and though it’s hard to measure I’d warrant it measures to at least 8 cm. Together with a backdrop of light gray microcrystalline stilbite and some larger stilbite crystals, this piece makes for a phenomenal display. As with a lot of cavansite from these finds, the color is difficult to capture on camera, and pops out a lot more when viewing in person. The backside of this specimen has been rounded out and the bottom cut straight, so it stands up on its own with no base. This medium size cabinet piece is truly world class in terms of visuals and would make a gorgeous addition to any collection.
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MORE INFO
Wagholi's quarries cut through the Deccan Volcanic Province, one of the largest flood basalt sequences on earth, active roughly 66 Ma - cavansite and its dimorph pentagonite formed specifically within flow-top breccia horizons of the lower Khandala Formation rather than in the more typical vesicular basalt that hosts the district's zeolites. A 2025 formation study by Ottens, Duraiswami, and Krenn based on fifty years of field observation constrained crystallization to roughly 120–200°C at low pressure, contemporaneous with associated low-temperature zeolites from which the hydrothermal fluids circulated through interconnected open spaces - isolated vesicles and open fractures producing distinct paragenetic sequences. Vanadium in the crystal structure is responsible for the deep cerulean to teal-blue color. Cavansite grows as rosette-like spherical aggregates of prismatic crystals typically on stilbite, heulandite, or - most prized by collectors - snow-white mordenite matrix, the contrast between deep blue and white being the defining aesthetic of the locality. Significant specimen production began in 1988 following Arvind Bhale's excavation of a previously unworked andesite horizon; only four of the complex's forty quarries have ever yielded the species. Quarrying restrictions tied to blast damage to adjacent residential areas have progressively curtailed access, and the Ottens et al. paper notes that the original productive zones are now degraded beyond investigation - making fresh material increasingly difficult to source.