Goyazite mineral
Goyazite is the strontium aluminium phosphate mineral SrAl3(PO4)(PO3OH)(OH)6, distinct from calcium-dominant crandallite, other crandallite-group species and strontium as an element. A primary natural-crystal refinement supports its identity. A separate laboratory study produced goyazite-bearing synthetic preparations and measured thermal dehydroxylation across a nominal calcium-strontium series. Minor impurities, starting-gel composition and measurement-dependent thermal peaks limit interpretation. No microbial mechanism, strontium recovery yield, mineral criticality or industrial deployment is asserted.
Microbial & Biochemical Mechanisms (1)
Abiotic synthesis and thermal dehydroxylation of goyazite-bearing solids
other
Replacing calcium chloride with strontium chloride in the reagent synthesis produced a goyazite-bearing nominal strontium endmember and intermediate compositions. Heating caused structural-water loss. This is an abiotic laboratory transformation of synthetic preparations, not biological strontium immobilization or recovery from a real feed.
Experimental Context & Analytical Limits:
Gilkes1983 Materials and methods (page 221, PDF page 1) crystallized gels made from sodium aluminate, calcium chloride and phosphoric acid, substituting strontium chloride for calcium chloride across the series. Gels were held for two weeks at 200 degrees C and 1.5 million N/m2 in a stainless-steel pressure vessel with a glass insert. Powder XRD used a quartz internal standard. TGA and differentiated TGA used 10 mg samples in flowing air at 10 degrees C/min; DTA used 100 mg under the same stated heating conditions. Exact starting reagent amounts, independent synthesis replicates and an isolated-product yield are not reported in this article. This is the same experimental series curated in the companion mineral record, not independent replication.
Gilkes1983 Materials and methods (page 221, PDF page 1) crystallized gels made from sodium aluminate, calcium chloride and phosphoric acid, substituting strontium chloride for calcium chloride across the series. Gels were held for two weeks at 200 degrees C and 1.5 million N/m2 in a stainless-steel pressure vessel with a glass insert. Powder XRD used a quartz internal standard. TGA and differentiated TGA used 10 mg samples in flowing air at 10 degrees C/min; DTA used 100 mg under the same stated heating conditions. Exact starting reagent amounts, independent synthesis replicates and an isolated-product yield are not reported in this article. This is the same experimental series curated in the companion mineral record, not independent replication.
Curated Evidence Points:
Context_only
Source:
ima_2026_09
The exact Goyazite row gives SrAl3(PO4)(PO3OH)(OH)6 and status Rd, 1999 s.p.; list definitions identify a redefined mineral. The entry confers no jurisdictional criticality designation.
Context_only
Source:
handbook_goyazite
The complete entry supports the ideal strontium endmember, natural diffraction and variable Ca/Ba/F-bearing compositions. Natural substitutions should not be confused with the nominal composition of a synthetic starting gel.
Context_only
Source:
kato1987
Experimental section and Tables 1-3 (pages 390-393, PDF pages 1-4) report a natural crystal from the North Groton, New Hampshire specimen supplied by the Smithsonian, NMNH 141049. Single-crystal refinement used 417 independent reflections with R=0.039 and reported a=7.015(3), c=16.558(6) angstrom and R-3m symmetry. Figures 1-2 (pages 394-395, PDF pages 5-6) depict the structural arrangement and hydrogen-related difference-Fourier section. This is direct natural-mineral structural evidence, not a synthesis or leaching experiment; the older 1971 study is the same locality/refinement lineage, not independent biological evidence.
Support
Source:
gilkes1983
Pages 221-224, Table II and Figure 1 report the nominal strontium endmember as goyazite with a=7.013 and c=16.650 angstrom, and approximately linear lattice changes with the starting-gel Sr proportion. The larger synthetic c parameter differs from natural goyazite measurements; authors propose natural cation substitution as an explanation, not a direct occupancy measurement in these preparations.
Partial
Source:
gilkes1983
Pages 221-223, Figure 1 and Table II identify crandallite-goyazite as the major series phases but explicitly report minor boehmite and strontium-substituted hydroxylapatites. The composition axis is mole percent Sr in the original gel, not a measured phase-specific Sr occupancy. Unit-cell estimates use only the well-resolved 303 and 220 reflections because other assignments are uncertain. Neither a pure endmember recovery yield nor a quantitative phase fraction follows from these measurements.
Support
Source:
gilkes1983
Pages 225-226 and Figures 5-6 show multiple thermal-water-loss features for goyazite-bearing material. The major DTGA feature is approximately 440 degrees C in the nominal strontium endmember; its corresponding DTA peak is appreciably higher. The weak high-temperature feature around 550 degrees C is attributed to boehmite. Thus a single universal goyazite decomposition temperature is not established.
Partial
Source:
gilkes1983
Pages 225-226 and Figures 5-6 distinguish DTA from DTGA peak temperatures; DTA peaks are systematically higher, possibly because its larger sample slows water escape. The highest-temperature feature is assigned to boehmite impurity, not the phosphate mineral. Differences in crystal size also confound a composition-only explanation. Table I compiles earlier literature, including substituted or mixed natural specimens; those entries are not new experiments or universal decomposition thresholds. The six-hour furnace series and residual-cell changes in Figure 7 were performed on crandallite, not goyazite; those transformation fractions and cell changes are not transferred to this owner.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026; definitions PDF page 1, Crandallite page 50 and Goyazite page 85, both redefined (Rd), 1999 special procedure.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15) -
handbook_goyazite: Handbook of Mineralogy, Goyazite, complete one-page identity entry; ideal formula, natural diffraction and substituted compositions.
https://handbookofmineralogy.org/pdfs/goyazite.pdf (accessed 2026-10-15) -
kato1987: Kato (1987). Further refinement of the goyazite structure. Mineralogical Journal 13(6):390-396. Complete seven-page original from J-STAGE, Tables 1-3 and Figures 1-2.
https://doi.org/10.2465/minerj.13.390 (accessed 2026-10-15) -
gilkes1983: Gilkes and Palmer (1983). Synthesis, properties, and dehydroxylation of members of the crandallite-goyazite series. Mineralogical Magazine 47:221-227. Complete seven-page original, Tables I-II and Figures 1-7; acquired from RRUFF current .net archive.
https://doi.org/10.1180/minmag.1983.047.343.13 (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T07:20:51.428952Z |
codex (GPT-6; codex) | CREATE | Added a distinct mineral with complete primary-supported abiotic transformation, verified identity, explicit phase impurities and experimental scope; no inherited criticality or microbial recovery claim. |
Record source: data/records/goyazite.yaml