Wavellite: Arkansas Radial Mineral

Wavellite is a rare phosphate mineral that crystallizes into clusters, stalactites, needle-like crystals, or spherical structures.

Wavellite is a mineral that demonstrates the classic radiating globule crystal habit. In fact, you could say that wavellite is the type mineral for this habit. The habit produces a unique effect when the globules are imbedded in limestone and chert. 

 Wavellite is a very attractive mineral, well-known to collectors. Its radial aggregate crystal clusters can be cut into extremely interesting stones.

 Wavellite is a phosphate mineral with formula Al3(PO4 )2(OH, F)3·5H2O. It normally occurs as translucent green radial or spherical clusters.

 Wavellite exhibits different shades of green, which range from dark emerald green, apple green, bright green, to pale green.

 It usually occurs in globular or hemispherical aggregates of botryoidal crusts on matrix, radiating crystals, or stalactitic deposits.

Wavellite
Wavellite: Arkansas Radial Mineral. Wavellite from the Avant Mine, Garland County, Arkansas, showing spherical structure
Photo: Rob Lavinsky

A secondary mineral found most often in aluminous, low-grade metamorphic rocks. Usually found as radiating "starburst" clusters of green to yellow-green fibrous crystals on fracture surfaces in the matrix, these may grade into globular aggregates; more rarely in chalcedony-like or opaline masses, or stalactic; very rare as good distinct crystals.

It occurs in association with crandallite and variscite in fractures in aluminous metamorphic rock, in hydrothermal regions and in phosphate rock deposits. It is found in a wide variety of locations notably in the Mount Ida, Arkansas area in the Ouachita Mountains.

 It’s named after the English physician who first discovered it, William Wavell.

  • Formula: Al3(PO4)2(OH,F)3 · 5H2O
  • Colour: Green to yellowish-green and yellow, greenish white, yellowish-brown, brown, brownish-black, blue, white and colourless; colourless in transmitted light.
  • Luster is vitreous.
  • Transparency crystals are transparent to translucent.
  • Crystal System is orthorhombic; 2/m 2/m 2/m
  • Hardness: 3½ - 4
  • Specific Gravity: 2.36
  • Type Locality:  High Down Quarry, West Buckland, North Devon, Devon, England, UK

 Comments
When broken across the spheres, wavellite exhibits a radial crystalline structure - the local old timers call it "cats-eye". Color may vary from light to dark green at this locale, the intensity of the color is due to how much vanadium is present in the structure of the mineral.

See Also:
 Where to Find Sunstone in Oregon?
 Different Types and Colours of Moonstone
What Is Pseudomorph Mineral?
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