Wavellite
Image: Andrew Silver (Public domain)
Mineral NameWavellite
Chemical FormulaAl3(PO4)2(OH,F)3·5H2O
Mohs Hardness3.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
CleavageGood on {110}
Fractureuneven
Specific Gravity2.35
Colorsgreen, yellowish-green, white, colorless, brown, blue, black
Transparencytransparent
Type LocalityMontgomery County, Arkansas, USA
Mineral GroupPhosphates
Usescollector, minor industrial
Associated Mineralslimonite, variscite, crandallite, turquoise
Rarityuncommon
Description
This specimen of Wavellite features distinctive radiating, hemispherical or spherulitic aggregates of acicular crystals, displaying a vibrant yellowish-green color. The individual crystals are too fine to be seen distinctly, forming a botryoidal or globular habit.
Geological Context
Wavellite is a secondary mineral found in low-grade metamorphic aluminous rocks, phosphate-rich deposits, and limonite beds. It forms from the alteration of other phosphate minerals, often in cracks and fissures.
