What is Wardite?
Wardite is a hydrated sodium aluminium phosphate, usually pale green to white and associated with phosphate-rich cavities and aluminium-bearing rocks.
Mineralogy and structure
Reference formula: NaAl3(PO4)2(OH)4·2H2O. Wardite is tetragonal with the ideal formula NaAl3(PO4)2(OH)4·2H2O. COD 9009442 is an exact structural reference; minor substitutions can occur in natural material. Wardite is classified with phosphates and has tetragonal crystal symmetry. Typical hardness is 3–3.5 on the Mohs scale and specific gravity is approximately 2.8–3.0.
Colour, lustre and habit
Typical colours include colourless, white, pale green, blue-green, yellowish. The usual pyramidal, botryoidal, crusty habit and vitreous, pearly, waxy lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Wardite forms in or is associated with phosphate-rich granite pegmatites, cave or weathering cavities and secondary phosphate deposits. Important documented localities include Utah in the United States, Brazil, Australia, Germany and Portugal.
Soft pale phosphate with a clean geometric habit
Wardite is attractive as a cabinet mineral because its quiet colour lets crystal form and matrix texture lead. Sharp pyramidal crystals and documented phosphate localities are the strongest selling points.
Collecting and care
Protect from acids, soaking and scratches; keep delicate crusts supported and retain the phosphate association.
