Wavellite
| Wavellite | |
|---|---|
 Wavellite cluster from Mauldin Mountain Quarries, Mauldin Mt., Montgomery County, Arkansas | |
| General | |
| Category | Phosphate minerals |
| Formula (repeating unit) | Al3(PO4)2(OH,F)3·5H2O |
| IMA symbol | Wav[1] |
| Strunz classification | 8.DC.50 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pcmn |
| Unit cell | a = 9.621 Å b = 17.363 Å, c = 6.994 Å; Z = 4 |
| Identification | |
| Color | Green to yellowish-green and greenish blue and blue. and yellow, brown, white and colorless |
| Crystal habit | Spherical, radial aggregates; striated prisms; crusty to stalactitic |
| Cleavage | [110] perfect, [101] good, [010] distinct |
| Fracture | Uneven to subconchoidal |
| Mohs scale hardness | 3.5 - 4 |
| Luster | Vitreous to resinous, pearly |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2.36 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.518 - 1.535 nβ = 1.524 - 1.543 nγ = 1.544 - 1.561 |
| Birefringence | δ = 0.026 |
| Pleochroism | Weak; X = greenish; Z = yellowish |
| 2V angle | Measured: 60° to 72° |
| Fusibility | Infusable, swells and splits on heating |
| Solubility | Insoluble |
| References | [2][3][4][5] |
Wavellite is an aluminium basic phosphate mineral with formula Al3(PO4)2(OH, F)3·5H2O. Distinct crystals are rare, and it normally occurs as translucent green radial or spherical clusters.[6]
Discovery and occurrence
[edit]
Wavellite was first described in 1805 for an occurrence at High Down, Filleigh, Devon, England and named by William Babington in 1805 in honor of Dr. William Wavell (1750–1829),[4] a Devon-based physician, botanist, historian, and naturalist, who brought the mineral to the attention of fellow mineralogists.[7][4][6][8]
It occurs in association with crandallite and variscite in fractures in aluminous metamorphic rock, in hydrothermal regions and in phosphate rock deposits.[2] It is found in a wide variety of locations notably in the Mount Ida, Arkansas area in the Ouachita Mountains.
It is sometimes used as a gemstone.[9]
See also
[edit]- List of minerals
- Apatite, fluoro-phosphate of calcium
- Pyromorphite, chloro-phosphate of lead
- Turquoise, a hydrated phosphate of copper and aluminium
References
[edit]- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Handbook of Mineralogy
- ^ Webmineral
- ^ a b c Mindat
- ^ Klein, Corneis and Cornelius S. Hurlbut, Jr., Manual of Mineralogy, Wiley, 20th ed. 1985, p. 362-3 ISBN 0-471-80580-7
- ^ a b Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica. Vol. 28 (11th ed.). Cambridge University Press. p. 430.
- ^ Green, David; Cotterell, Tom; Jones, I.; Cox, D.; Cleevely, R. (2007). "Wavellite: its discovery and occurrences in the British Isles". UK Journal of Mines and Minerals. 28: 11–30.
- ^ Curtis, Samuel and Hooker, William Jackson (1827). Memoirs of the Life and Writing of the Late Mr. William Curtis, Curtis's Botanical Magazine; or Flower Garden Displayed, v. 1 (new series), v-xxxii.
- ^ Gemstones: Properties, identification and use by Arthur Thomas, p. 132.
External links
[edit]- "Wavellite at museum of Barnstaple and North Devon". Retrieved 9 May 2020.
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