Aiolosite, Na2(Na2Bi)(SO4)3Cl, a new sulfate isotypic to apatite from La Fossa Crater, Vulcano, Aeolian Islands, Italy

Researchers have discovered aiolosite, a new sulfate mineral isotypic to apatite, in the active medium-temperature intracrater fumarole of La Fossa crater on Vulcano Island, part of Italy's Aeolian Islands. Aiolosite, with the ideal formula Na2(Na2Bi)(SO4)3Cl, occurs as acicular to slender prismatic crystals up to 0.5 mm long, often found alongside alunite, anhydrite, and other minerals in altered pyroclastic breccia. The mineral exhibits hexagonal symmetry, a vitreous luster, and is non-fluorescent with a calculated density of 3.589 g/cm³. Its crystal structure reveals that one Ca site in apatite is exclusively occupied by Na, while the other is statistically distributed between Na and Bi. The SO4²⁻ anion replaces PO4³⁻ in apatite, and chloride or water occupies a partially filled position. The discovery was approved by the IMA CNMNC (No. 2008-015) and represents a significant contribution to mineralogical research.

Demartin, F., Gramaccioli, C. M., Campostrini, I., & Pilati, T. (2010). Aiolosite, Na2(Na2Bi)(SO4)3Cl, a new sulfate isotypic to apatite from La Fossa Crater, Vulcano, Aeolian Islands, Italy. American Mineralogist, 95(2-3), 382–385. https://doi.org/10.2138/am.2010.3337