Referenza:
▪ Elliott, P., Grey, I.E., Mumme, W.G., MacRae, C.M., Kampf, A.R. (2022): Tomsquarryite, NaMgAl3(PO4)2(OH)6●8H2O, a new crandallite-derivative mineral from Tom's phosphate quarry, Kapunda, South Australia. European Journal of Mineralogy, 34, 375–383.
Abstract:
Tomsquarryite, NaMgAl3(PO4)2(OH)6•8H2O, is a new secondary phosphate mineral from Tom's phosphate quarry, Kapunda, South Australia. It occurs as colourless, talc-like hexagonal platelets, with diameters of a few tens of micrometres when formed from the decomposition of minyulite and as thicker (∼ 10 µm) hexagonal crystals when formed from alteration of gordonite. Associated minerals are penriceite, elliottite, minyulite, angastonite and wavellite. The calculated density is 2.22 g cm−3. Tomsquarryite crystals are uniaxial (+) with ω=1.490(3), ε=1.497(3) (white light). Dispersion was not observed. The partial orientation is Z≈c. Electron microprobe analyses of the holotype specimen give the empirical formula Na1.02K0.02Ca0.08Mg1.26Al2.86(PO4)2.00(OH)3.82F2.48 • 7.70H2O, based on 22 anions. Tomsquarryite belongs to the trigonal crystal system, space group R–3m, with hexagonal unit-cell parameters a=6.9865(5) Å, c=30.634(3) Å and V=1294.9(4) Å3 and with Z=3. The crystal structure was refined using single-crystal diffraction data; R1=0.069 for 303 reflections with I>2σ(I) to a resolution of 0.80 Å. The crystal structure is a derivative of the crandallite structure, with Ca2+ cations replaced by hydrated magnesium ions, [Mg(H2O)6]2+, resulting in an expansion of the interlayer separation from 5.4 Å in crandallite to 10.2 Å in tomsquarryite. The results for tomsquarryite are compared with those for the chemically and structurally related minerals penriceite and elliottite.
NdR: Le specie del supergruppo dell'alunite ora sono 61.
IMA 2022-018 = tomsquarryite
- Marco E. Ciriotti
- Messaggi: 31645
- Iscritto il: ven 25 giu, 2004 11:31
- Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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IMA 2022-018 = tomsquarryite
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
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