Phosphophyllite

Phosphophyllite
General
Category	Phosphate minerals
Formula (repeating unit)	hydrated zinc phosphate (Zn2Fe(PO4)2·4H2O)
IMA symbol	Pp[1]
Strunz classification	8.CA.40
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P21/c
Identification
Formula mass	448.40 g/mol
Color	Blue-green to colourless
Crystal habit	Prismatic
Twinning	Common
Cleavage	[100] Perfect, [010] Distinct, [102] Distinct
Fracture	Conchoidal
Mohs scale hardness	3.5
Luster	Vitreous
Streak	White
Diaphaneity	Transparent
Specific gravity	3.1
Optical properties	Biaxial (−)
Refractive index	nα = 1.595–1.599, nβ = 1.614–1.617, nγ = 1.616–1.620
Birefringence	0.021
2V angle	Measured 44°, Calculated 34°
Common impurities	Manganese
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 × 1.4 × 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 by the addition of diammonium phosphate to a solution of zinc and iron sulfate.^[6]

Popular culture

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.^[7]

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.
7. Zhang, Mary (2020-08-06). "Land of the Lustrous: Crystal Gems..." CBR. Retrieved 2024-04-21.