Metavivianite

Hydrated iron phosphate mineral
(repeating unit)Fe2+
Fe3+
2(PO
4)
2(OH)
2·6H
2OIMA symbolMviv[1]Strunz classification8.DC.25 (10 ed)
7/C.14-20 (8 ed)Dana classification40.11.9.4Crystal systemTriclinicCrystal classPinacoidal (1)
Space groupP1barUnit cella = 7.989(1) Å, b = 9.321(2) Å
c = 4.629(1) Å; α = 97.34(1)°; β = 95.96(1)°; γ = 108.59(2)°IdentificationFormula mass499.548 g/molColorDark blue to blue-black; Dark green to green-blackCrystal habitBladed crystals, often with irregular acute multiple terminations.Twinning{110}CleavagePerfect on {110}TenacitySectileMohs scale hardness1.5–2LusterSub-vitreous, Resinous, Greasy, DullStreakBlue or greenish blueDiaphaneitytranslucentSpecific gravity2.69Optical propertiesBiaxial (+)Refractive indexnα = 1.600 – 3.000, nβ = 1.640 – 3.000, nγ = 1.685 – 3.000[2]Birefringenceδ = 0.050 – 0.085PleochroismVisible; X = blue to blue-green; Y,Z = yellow-green2V angleMeasured: 85° (5), Calculated: 90°DispersionVery weakUltraviolet fluorescenceNot fluorescentReferences[2][3][4]

Metavivianite (Fe2+
Fe3+
2(PO
4)
2(OH)
2·6H
2O) is a hydrated iron phosphate mineral found in a number of geological environments. As a secondary mineral it is typically formed from oxidizing vivianite.[2] Metavivianite is typically found as dark blue or dark green prismatic to flattened crystals.

It was named by C. Ritz, Eric J. Essene, and Donald R. Peacor in 1974 for its structural relationship to vivianite.[3]

See also

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b c John W. Anthony; Richard A. Bideaux; Kenneth W. Bladh & Monte C. Nichols (2005). "Handbook of Mineralogy" (PDF). Mineral Data Publishing. {{cite journal}}: Cite journal requires |journal= (help)
  3. ^ a b Metavivianite (Mindat.org)
  4. ^ Metavivianite Webmineral Data


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