Svanbergite mineral

Svanbergite is the strontium aluminium sulfate-phosphate mineral SrAl3(SO4)(PO4)(OH)6, distinct from calcium-dominant woodhouseite, strontium aluminium phosphate goyazite and strontium as an element. The September 2026 IMA list records its redefinition by special procedure in 1987. Kato and Miura (1977) refined a natural crystal from Dover Andalusite Mine, Nevada, British Museum specimen BM 17702. Single-crystal diffraction used 283 reflections and supported R-3m symmetry, a=6.992(2) and c=16.567(5) angstrom, with R=0.085. This specimen-specific structure contains disordered phosphorus/sulfur tetrahedral sites; the paper does not provide a new chemical analysis of that exact crystal or locate all hydrogen atoms directly. Its separate jarosite specimen and comparisons with earlier structures are not svanbergite synthesis experiments. Stoffregen and Alpers (1987) measured variable natural aluminium phosphate-sulfate grains in three hydrothermal ore deposits. Svanbergite-rich grains accompany alunite or kaolinite in shallower Summitville material, while La Escondida includes intermediate Ca/Sr compositions assigned probable hypogene or supergene origins from textures. Figure 1 shows a grain with subequal Ca and Sr rather than a pure svanbergite endmember; Table 3 and Figure 2 retain compositional variation and calculated water. Replacement or dissolution of apatite in acidic, sulfate-rich alteration is a geological interpretation, not a time-resolved transformation assay or demonstrated microbial mechanism. The 250 degrees C stability diagram in Figure 3 is a calcium-system woodhouseite inference and must not be treated as an experimentally measured svanbergite stability field. The companion woodhouseite record uses the same field-study lineage. Mineral identity and qualified natural alteration context are supported; microbial formation, strontium recovery yield, industrial deployment and mineral-specific criticality are not asserted.

Record source: data/records/svanbergite.yaml