Wardite Explained

Wardite
Category:Phosphate minerals
Formula:NaAl3(PO4)2(OH)4·2(H2O)
Imasymbol:Wd[1]
Strunz:8.DL.10
System:Tetragonal
Class:Trapezohedral (422)
H-M symbol: (4 2 2)
Symmetry:P41212
Unit Cell:a = 7.03(1), c = 19.04(1) Å;
Z = 4
Color:White, colorless, pale green, blue-green, yellow-green, pale yellow, yellow pink.
Habit:Dipyramidal pseudo-octahedral crystals, striated; radial, fibrous, encrustations
Cleavage:Perfect on
Mohs:5
Luster:Vitreous
Diaphaneity:Transparent to opaque
Gravity:2.81–2.87
Opticalprop:Uniaxial (+)
Refractive:nω = 1.586 – 1.594 nε = 1.595 – 1.604
Birefringence:δ = 0.009
2V:0.0
References:[2] [3] [4]

Wardite is a hydrous sodium aluminium phosphate hydroxide mineral with formula: NaAl3(PO4)2(OH)4·2(H2O). Wardite is of interest for its rare crystallography. It crystallizes in the tetragonal trapezohedral class and is one of only a few minerals in that class. Wardite forms vitreous green to bluish green to white to colorless crystals, with pyramidal or faces and with usually present masses. Also appera as fibrous encrustations. It has a Mohs hardness of 5 and a specific gravity of 2.81–2.87.[5]

Wardite was named for Henry Augustus Ward (1834–1906) of the University of Rochester in New York. It first described in 1896 for an occurrence in Clay Canyon, Fairfield, Utah County, Utah, US.

Occurrence

It occurs with variscite in phosphate nodules and occurs uncommonly in pegmatites and phosphate deposits through alteration of amblygonite.

Wardite is a rare mineral, which has been found in approximately 70 locations worldwide, but generally on a microscopic scale, with only a few occurrences of significant specimens.[6] The finest specimens, boasting crystals up to 4 cm in size, originate from Rapid Creek and the Big Fish River in the Dawson mining district, Alaska (USA).[7] Good quality specimens, measuring up to 1 cm, have also been discovered in Lavra da Ilha, Taquaral, Itinga, Minas Gerais, Brazil. In Spain, it appears in the form of crystals up to 1 cm found in cavities within montebrasite at the Tita mine in Golpejas, Salamanca.[8]

See also

References

Notes and References

  1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
  2. http://rruff.geo.arizona.edu/doclib/hom/wardite.pdf Handbook of Mineralogy
  3. http://www.mindat.org/min-4242.html Mindat.org
  4. http://webmineral.com/data/Wardite.shtml Webmineral data
  5. Book: Gaines, R.V., W. Skinner, C.W., Foord, E.E., Mason, B. Rosenzweig, A. . Dana's new mineralogy . John Wiley & Sons, Inc. . 1997 . 9780471193104 . New York, US . 905.
  6. Web site: Wardite. Mindat .
  7. Robinson, G. W., Van Velthuizen, J, Ansell, H. G. y Sturman, B.D . Mineralogy of the Rapid Creek and Big Fish River Area, Yukon Territory . The Mineralogical Record . 23 . 1–47.
  8. Book: Calvo, Miguel . Minerales y Minas de España. Vol. VII. Fosfatos, Arseniatos y Vanadatos . Escuela Técnica Superior de Ingenieros de Minas de Madrid. Fundación Gómez Pardo . 2015 . Madrid, Spain . 2015 . 385 . es . Minerals and Mines of Spain. Vol. VII. Phosphates, Arsenates and Vanadates.