Wardite is a hydrous sodium aluminium

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It ...

mineral with formula: Na Al₃( P O₄)₂(O H)₄·2( H₂O). Wardite is of interest for its rare crystallography. It crystallizes in the

tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the Cube (geometry), cube becomes a rectangular Pri ...

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 appears as fibrous encrustations. It has a

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 5 and a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

of 2.81–2.87. Wardite was named for Henry Augustus Ward (1834–1906) of the

University of Rochester The University of Rochester is a private university, private research university in Rochester, New York, United States. It was founded in 1850 and moved into its current campus, next to the Genesee River in 1930. With approximately 30,000 full ...

in New York. It first described in 1896 for an occurrence in Clay Canyon, Fairfield, Utah County,

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, US.

Occurrence

It occurs with variscite in phosphate nodules and occurs uncommonly in

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic c ...

s 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. 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). 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.

References

{{commons category, Wardite
Mineral galleries
Sodium minerals Aluminium minerals Phosphate minerals Tetragonal minerals Minerals in space group 92

Occurrence

See also

References