Wardite

Wardite
Wardite from Rapid Creek – Yukon, Canada
General
Category	Phosphate minerals
Formula (repeating unit)	NaAl3(PO4)2(OH)4·2(H2O)
Strunz classification	8.DL.10
Crystal system	Tetragonal
Crystal class	Trapezohedral (422) H-M symbol: (4 2 2)
Space group	P41212
Unit cell	a = 7.03(1), c = 19.04(1) Å; Z = 4
Identification
Color	White, colorless, pale green, blue-green, yellow-green, pale yellow, yellow pink.
Crystal habit	Dipyramidal pseudo-octahedral crystals, striated; radial, fibrous, encrustations
Cleavage	Perfect on {001}
Mohs scale hardness	5
|re|er}}	Vitreous
Diaphaneity	Transparent to opaque
Specific gravity	2.81–2.87
Optical properties	Uniaxial (+)
Refractive index	nω = 1.586 – 1.594 nε = 1.595 – 1.604
Birefringence	δ = 0.009
2V angle	0.0
References	[1][2][3]

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, masses, and fibrous encrustations. It has a Mohs hardness of 5 and a specific gravity of 2.81–2.87.

Occurrence

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

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. Though rare it has been reported from many locations worldwide.

See also

• List of minerals
• List of minerals named after people

References

• Mineral galleries

0.00 (0 votes) Original source: https://en.wikipedia.org/wiki/Wardite. Read more