wardite
{{Short description|A rare hydrated phosphate mineral}}
{{Infobox mineral
| name = Wardite
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| image = Wardite.jpg
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| caption = Wardite from Rapid Creek – Yukon, Canada
| category = Phosphate minerals
| formula = NaAl3(PO4)2(OH)4·2(H2O)
| molweight =
| strunz = 8.DL.10
| dana =
| 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.
| colour =
| habit = Dipyramidal pseudo-octahedral crystals, striated; radial, fibrous, encrustations
| twinning =
| cleavage = Perfect on {001}
| fracture =
| tenacity =
| mohs = 5
| luster = Vitreous
| streak =
| diaphaneity = Transparent to opaque
| gravity = 2.81–2.87
| density =
| polish =
| opticalprop = Uniaxial (+)
| refractive = nω = 1.586 – 1.594 nε = 1.595 – 1.604
| birefringence = δ = 0.009
| pleochroism =
| 2V = 0.0
| dispersion =
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| references = [http://rruff.geo.arizona.edu/doclib/hom/wardite.pdf Handbook of Mineralogy][http://www.mindat.org/min-4242.html Mindat.org][http://webmineral.com/data/Wardite.shtml Webmineral data]
}}
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 {102} or {114} faces and with {001} usually present masses. Also appears as fibrous encrustations. It has a Mohs hardness of 5 and a specific gravity of 2.81–2.87.{{Cite book |last=Gaines, R.V., W. Skinner, C.W., Foord, E.E., Mason, B. Rosenzweig, A. |title=Dana's new mineralogy |publisher=John Wiley & Sons, Inc. |year=1997 |isbn=9780471193104 |location=New York, US |pages=905}}
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.{{Cite web |title=Wardite. Mindat |url=https://www.mindat.org/min-4242.html}} 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).{{Cite journal |last=Robinson, G. W., Van Velthuizen, J, Ansell, H. G. y Sturman, B.D |title=Mineralogy of the Rapid Creek and Big Fish River Area, Yukon Territory |journal=The Mineralogical Record |volume=23 |pages=1–47}} 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.{{Cite book |last=Calvo |first=Miguel |title=Minerales y Minas de España. Vol. VII. Fosfatos, Arseniatos y Vanadatos |publisher=Escuela Técnica Superior de Ingenieros de Minas de Madrid. Fundación Gómez Pardo |year=2015 |location=Madrid, Spain |publication-date=2015 |pages=385 |language=es |trans-title=Minerals and Mines of Spain. Vol. VII. Phosphates, Arsenates and Vanadates}}
See also
References
{{Reflist}}
{{commons category|Wardite}}
- [http://mineral.galleries.com/minerals/phosphat/wardite/wardite.htm Mineral galleries]