Eosphorite mineral

Eosphorite is the Mn2+-dominant aluminium phosphate mineral with ideal formula Mn2+Al(PO4)(OH)2(H2O), distinct from Fe2+-dominant childrenite. The September 2026 IMA list records grandfathered status and original-description year 1878. Gatta et al. (2013) examined fragments of one natural crystal from the Chamachhu granitic pegmatite area in Pakistan. Their 22 electron-microprobe spots characterize this crystal rather than 22 independent specimens. The analysis gives Mn0.940 and Fe0.061 atoms per formula unit on a one-P basis; water was calculated using assumed anion stoichiometry. Neutron diffraction at 20 K supports an orthorhombic Cmca model and locates hydrogen sites. The refined mixed metal site contains Fe0.056(1), close to the chemical analysis, without evidence of additional Mn/Fe ordering in this low-Fe specimen. The model assigns O3 to hydroxyl and O4 to statistically shared hydroxyl/water configurations, with the two mirror-related H2 positions mutually exclusive and approximately half occupied. This corrects the hydroxyl/water assignment in Hoyos et al. (1993), whose different natural Taquaral specimen nevertheless supported the same general Cmca framework. The older paper's two-water formula in its introduction and Table 2 is not adopted over the one-water IMA formula and 2013 analysis. The 2013 chemical analysis includes fluorine, but attempted O/F occupancy refinement was not meaningful; its deposited model omits F and must not be read as complete measured composition. Table 5 and the discussion label an O4-H1-O4 angle where the accompanying short contact is described through H2, so no exact value for that disputed hydrogen-bond label is curated. These are specimen-specific structural observations, without a demonstrated extraction, formation or microbial recovery mechanism. No criticality designation is inherited from manganese, aluminium or phosphorus.

Record source: data/records/eosphorite.yaml