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Phosphophyllite

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Phosphophyllite
General
CategoryPhosphate minerals
FormulaZn2Fe(PO4)2·4H2O
IMA symbolPp[1]
Strunz classification8.CA.40
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/c
Identification
Formula mass448.40 g/mol
ColorBlue-green to colourless
Crystal habitPrismatic
TwinningCommon
Cleavage[100] Perfect, [010] Distinct, [102] Distinct
FractureConchoidal
Mohs scale hardness3.5
LusterVitreous
StreakWhite
DiaphaneityTransparent
Specific gravity3.1
Optical propertiesBiaxial (−)
Refractive indexnα = 1.595–1.599, nβ = 1.614–1.617, nγ = 1.616–1.620
Birefringence0.021
2V angleMeasured 44°, Calculated 34°
Common impuritiesManganese
References[2]

Phosphophyllite is a rare phosphate mineral with the chemical formula Zn2Fe(PO4)2·4H2O. It is prized among mineral collectors for its delicate bluish green colour, but rarely cut for its difficult properties.

Geology

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Phosphophyllite was first described in 1920 by Heinrich Laubmann and Hermann Steinmetz.[3] The name derives from from Ancient Greek phyllon 'leaf', and phosphate[4]

Chemically, phosphophyllite is related to zinc phosphate with some zinc substituted by iron. Phosphophyllite has been synthesized by the addition of diammonium phosphate to a solution of zinc and iron sulfate.[5]

Occurrence

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The finest phosphophyllite crystals come from Potosí, Bolivia, but it is no longer mined there. Other sources include New Hampshire, United States and Hagendorf, Bavaria, Germany. It is often found in association with the minerals chalcopyrite and triphylite.[6]

Uses

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Phosphophyllite is highly prized by collectors for its rarity and for its delicate bluish green colour but brittleness and fragility as well as the intrinsic value of large crystals make it unsuitable for jewelry.[7]

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Twinned phosphophyllite, Unificada Mine, Cerro de Potosí, Potosí Department, Bolivia. 2.1 × 1.4 × 1 cm
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An anthropomorphic form of phosphophyllite is the protagonist of the manga and anime series Land of the Lustrous, with key features of the mineral such as its brittle nature and vibrant color reflected in their character traits and design.[8]

References

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  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. ^ "Mineralatlas Lexikon - Phosphophyllite (english Version)". www.mineralienatlas.de.
  3. ^ Page Phosphophyllite: Mineral information, data and localities on "mindat.org". Hudson Institute of Mineralogy. Retrieved 2025-03-16.
  4. ^ "Phosphophyllite". Retrieved 2006-12-16.
  5. ^ Thomas, Ian M.; Weller, Mark T. (1992). "Synthesis, structure and thermal properties of phosphophyllite, Zn 2 Fe(PO 4 ) 2 ·4H 2 O". J. Mater. Chem. 2 (11): 1123–1126. doi:10.1039/JM9920201123. ISSN 0959-9428.
  6. ^ "The mineral phosphophyllite". Amethyst Galleries, Inc. Archived from the original on 2006-10-17. Retrieved 2006-12-16.
  7. ^ Hall, Cally (1994). Gemstones. Great Britain: Dorling Kindersley. p. 127. ISBN 0-7513-1026-3.
  8. ^ Zhang, Mary (2020-08-06). "Land of the Lustrous: Crystal Gems..." CBR. Retrieved 2024-04-21.