Wardite
Chemical formula: NaAl₃(PO₄)₂(OH)₄ · 2H₂O
Wardite is a rare hydrated sodium aluminum phosphate, typically forming small, tetragonal crystals, often with a bluish or greenish tint.
Description
## Characteristics Wardite is a hydrated sodium aluminum phosphate that usually occurs as small, well-formed bipyramidal or prismatic crystals. It often forms radial aggregates, spherical masses, or crusts. Wardite specimens can be colorless, white, and also take on delicate shades of blue, green, yellowish-green, light yellow, or brown. In transmitted light, it is colorless. ## Physical Properties Wardite has a Mohs hardness of 5. This mineral exhibits perfect cleavage along the {001} plane. Its density is 2.81 g/cm³. Wardite has a vitreous luster and can be transparent to opaque. ## Colors and Varieties Wardite occurs in colors ranging from colorless and white, through delicate shades of blue and green, to yellowish-green, light yellow, and brown. There are no specific commercial or color varieties. ## History and Name Wardite was discovered in 1896. The mineral is named after the American mineral collector, Henry A. Ward, who was the founder of Ward's Natural Science Establishment. ## Applications Wardite has no industrial applications due to its rarity and small crystal size. It is valued exclusively by mineral collectors.
Diagnostic features
## Identification Wardite can be identified by its tetragonal crystallographic system, often bipyramidal or prismatic crystal habit. Its characteristic colors, especially delicate shades of blue and green, and perfect cleavage are also distinctive. ## Distinguishing from Similar Minerals Wardite can be confused with other phosphates, but its tetragonal crystallographic system, specific cleavage, and crystal habit help in differentiation. Chemical analysis is the ultimate identification method. ## Crystal Forms Wardite most often forms bipyramidal or prismatic crystals. Radial aggregates, spherical masses, or crusts are also common.
Geological environment
## Genesis Wardite is a secondary mineral, forming in the oxidation zones of phosphate deposits, often in pegmatites, where it occurs in fissures and cavities. It forms as a result of low-temperature hydrothermal processes. ## Mineral Associations Wardite often co-occurs with other phosphate minerals, such as lazulite, augelite, zircon, as well as quartz and muscovite. ## Localities Known localities of wardite include the United States (e.g., Clay Canyon mine, Fairfield County, Utah; Big Chief mine, Pennington County, South Dakota), Brazil (Minas Gerais), and Canada (Yukon).
Rarity
Rare
Collector aspects
## Quality Criteria The most prized wardite specimens are those with well-formed, distinct crystals, with intense and uniform coloration (especially blue or green) and without visible damage. Crystal size also affects collectible value. ## Popular Localities Specimens from historical localities in the United States, such as the Clay Canyon mine in Utah, known for its aesthetic wardite crystals, are particularly sought after.
Care and storage
## Cleaning Wardite can be cleaned gently using a soft brush and lukewarm water. For more stubborn dirt, distilled water can be used to avoid hard water deposits. ## What to Avoid Avoid using strong chemical agents that can damage the mineral's surface. Wardite is not particularly sensitive to sunlight or temperature changes, but it is always advisable to avoid extreme conditions. ## Storage Wardite specimens are best stored in enclosed display cases or boxes, protecting them from dust and accidental mechanical damage. Due to its hardness (5 on the Mohs scale), contact with harder minerals that could scratch it should be avoided.