Phosphophyllite
General
CategoryPhosphate minerals
Formula
(repeating unit)		hydrated zinc phosphate (Zn2Fe(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 (from Ancient Greek phyllon 'leaf', and phosphate[3]) is a rare mineral with the chemical formula Zn2Fe(PO4)2·4H2O, composed of hydrated zinc phosphate. It is highly prized by collectors for its rarity and for its delicate bluish green colour. Phosphophyllite is rarely cut because it is fragile and brittle, and large crystals are too valuable to be broken up.[4]

Twinned Phosphophyllite, Unificada Mine, Cerro de Potosí, Potosí Department, Bolivia. 2.1 x 1.4 x 1 cm.

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.[5]

Phosphophyllite has been synthesized synthetically by the addition of diammonium phosphate to a solution of zinc and iron sulfate.[6]

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. ↑ "Mineralatlas Lexikon - Phosphophyllite (english Version)". www.mineralienatlas.de.
  3. ↑ "Phosphophyllite". Retrieved 2006-12-16.
  4. ↑ Hall, Cally (1994). Gemstones. Great Britain: Dorling Kindersley. p. 127. ISBN 0-7513-1026-3.
  5. ↑ "The mineral phosphophyllite". Amethyst Galleries, Inc. Archived from the original on 2006-10-17. Retrieved 2006-12-16.
  6. ↑ 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.
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