Augelite

Aluminium phosphate mineral
(repeating unit)Al2(PO4)(OH)3IMA symbolAul[1]Strunz classification8.BE.05Crystal systemMonoclinicCrystal classPrismatic (2/m)
(same H-M symbol)Space groupC2/mUnit cella = 13.124(6), b = 7.988(5)
c = 5.0633(3) [Å]
β = 112.25(2)°; Z = 4IdentificationColorColorless to white, may be yellowish to pale rose, greenishCrystal habitTabular to prismatic or acicular crystals; massiveCleavagePerfect on {110}, good on {201}, imperfect on {001} and {101}FractureUnevenTenacityBrittleMohs scale hardness4 – 4.5LusterVitreous, pearly on {110} cleavageStreakWhiteDiaphaneityTransparentSpecific gravity2.696Optical propertiesBiaxial (+)Refractive indexnα = 1.574 nβ = 1.576 nγ = 1.588Birefringenceδ = 0.0142V angleMeasured: 50°References[2][3]

Augelite is an aluminium phosphate mineral with formula: Al2(PO4)(OH)3. The shade varies from colorless to white, yellow or rose. Its crystal system is monoclinic.[4]

It was first described by Christian Wilhelm Blomstrand for an occurrence in Västanå iron mine at Scania, Sweden in 1868 and derives its name from the Greek αύγή in reference to its pearly lustre.[2][3]

It occurs as a product of metamorphism of phosphate bearing peraluminous sediments and in high-temperature hydrothermal ore deposits. It occurs in association with attakolite, svanbergite, lazulite, hematite, trolleite, berlinite, rutile, pyrophyllite, baryte, arsenopyrite, stannite, pyrite, andorite, cassiterite and zinkenite.[2]

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 Handbook of Mineralogy
  3. ^ a b Mindat.org
  4. ^ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: "Dana's new mineralogy", p. 851. John Wiley & Sons, 1997
Wikimedia Commons has media related to Augelite.


  • v
  • t
  • e