Wavellite
Wavellite is Al3(PO4)2(OH,F)3·5H2O: radial balls to 3 cm, hardness 3.5 to 4, density 2.36. Named for William Wavell of Devon; abundant near Avant, Arkansas.
Wavellite is a hydrated aluminium phosphate, Al3(PO4)2(OH,F)3·5H2O, commonly in flat to spherical radial aggregates to 3 cm: orthorhombic, hardness 3.5 to 4, measured density 2.36, white streak, colour from white and green to turquoise-blue. A 20.00 g piece reads 11.53 g in water, against 12.22 to 12.34 g for variscite. It is named for William Wavell of Devon.
In short
- Two formulas. The September 2026 IMA-CNMNC Master List writes Al3(PO4)2(OH)3(H2O)5, status A, 1971 special procedure, United Kingdom. The Handbook of Mineralogy sheet writes Al3(PO4)2(OH,F)3·5H2O, allowing fluorine for hydroxyl. Both are shown here, attributed.
- The phosphate ladder. Worked as 20 − 20/D from the sheets, a 20.00 g piece reads 11.53 g in water as wavellite, 12.22 to 12.34 g as variscite and 13.01 g as turquoise: steps of 0.69 g and 0.67 g. Hardness climbs the same way: 3.5 to 4, 4.5, then 5 to 6.
- Documented failure: colour and streak. The wavellite sheet lists green and turquoise-blue among its colours, and wavellite and variscite both print a white streak; turquoise prints white to pale greenish blue. Colour and streak will not separate the three. The turquoise sheet also prints density 2.86 less if massive, so a porous piece can slide down the ladder.
- The fluorine check. The sheet’s Clonmel, Ireland, analysis carries 2.79% F. Worked per two phosphorus atoms, that is 0.62 F, about 21% of the three (OH,F) sites. The IMA formula has none; the Handbook’s (OH,F) has room for it.
- Where. First on the sheet: the High Down quarry, Filleigh, near South Moulton (as the sheet prints it), Devon. In Arkansas, abundant around Avant, as on Dug Hill, Garland Co., and from the Mauldin Mountain quarry near Mt. Ida, Montgomery Co. Four localities appear on both the wavellite and variscite sheets.
| Species | IMA formula | IMA status, year | Hardness | Density (measured) | 20.00 g piece in water | Streak | Colours printed | Habit (Handbook) | Al:P |
|---|---|---|---|---|---|---|---|---|---|
| Wavellite | Al3(PO4)2(OH)3(H2O)5 | A, 1971 s.p. | 3.5 to 4 | 2.36 | 11.53 g | White | White, greenish white, green, yellow, yellowish brown, turquoise-blue, brown, brownish black | Flat to spherical radial aggregates to 3 cm | 1.5 |
| Variscite | Al(PO4)(H2O)2 | A, 1967 s.p. | 4.5 | 2.57 to 2.61 | 12.22 to 12.34 g | White | Pale green, emerald-green, bluish green, colourless, pale brown or yellow; rarely red | Usually fine-grained massive, nodules, crusts, veinlets | 1.0 |
| Turquoise | CuAl6(PO4)4(OH)8(H2O)4 | A, 1967 s.p. | 5 to 6 | 2.86, less if massive | 13.01 g (at 2.86) | White to pale greenish blue | Sky-blue, bluish green, apple-green, greenish grey | Fine granular to cryptocrystalline; nodular, crusts, veinlets | 1.5 |
What is wavellite? An aluminium phosphate in radial spheres
The names. The September 2026 IMA-CNMNC Master List gives Al3(PO4)2(OH)3(H2O)5, status A, year 1971 (special procedure), country United Kingdom. The Handbook sheet gives Al3(PO4)2(OH,F)3·5H2O and names it for William Wavell (?–1829), physician, of Horwood Parish, Devon, England, discoverer of the species. The sheet does not print a type locality, and this page does not supply one.
What it looks like. Orthorhombic. Euhedral crystals are uncommon, short to long prismatic, elongated and striated along [001], to several mm. The usual habit is flat to spherical radial aggregates, to 3 cm; it may also be stalactitic, in crusts, and rarely opaline and massive. Cleavage perfect on {110}, good on {101}, distinct on {010}; fracture uneven to subconchoidal; brittle. Hardness 3.5 to 4; measured density 2.36. Colours run from white and greenish white to green, yellow, yellowish brown, turquoise-blue, brown and brownish black, and may be zoned; streak white; lustre vitreous to resinous and pearly.
Composition, worked on standard atomic weights: formula mass 411.98, of which 34.45% is P2O5, 37.12% Al2O3 and 28.42% H2O, the sheet’s ideal column to within 0.01. The sheet places wavellite as a secondary mineral in low-grade metamorphic rocks and phosphate deposits, rare in hydrothermal veins, with crandallite and variscite. Radiating habits in general are explained on what botryoidal means.
Is it wavellite, variscite or turquoise? The phosphate ladder
The ladder. All three are aluminium phosphates. The wavellite sheet lists variscite among its associates and the turquoise sheet lists wavellite; the variscite sheet names neither. Weighed in water by the method on how to measure specific gravity at home, a 20.00 g piece reads 11.53 g as wavellite at 2.36, 12.22 to 12.34 g as variscite at 2.57 to 2.61, and 13.01 g as turquoise at 2.86. The steps are 0.69 g and 0.67 g, enough for a balance reading to 0.01 g on a clean piece.
Hardness runs the same way: wavellite 3.5 to 4, variscite 4.5, turquoise 5 to 6, per the sheets; the method is on how to test mineral hardness properly. Habit is the third check. Wavellite’s sheet describes radial aggregates to 3 cm; variscite’s gives usually fine-grained massive material in nodules and crusts, with crystals only to 1.5 mm; turquoise’s gives fine granular to cryptocrystalline, nodular and globular crusts.
Documented failures. Colour does not separate them: the wavellite sheet itself lists green and turquoise-blue. Streak does not separate wavellite from variscite, both white. And the turquoise sheet prints its density as 2.86, less if massive, so a porous turquoise can read lighter than 13.01 g and close the gap to variscite. Turquoise imitations and treatments are a separate question, on how to tell real turquoise from fake, whose method this page does not repeat.
Does wavellite contain fluorine? The Clonmel check
The two formulas differ on one point. The Handbook writes (OH,F)3, the IMA list (OH)3. The sheet’s analysis, from Clonmel, Co. Tipperary, Ireland, reads P2O5 33.40%, Al2O3 37.44%, Fe2O3 0.64%, F 2.79%, H2O 26.45%, less 1.17% for the oxygen equivalent of fluorine, total 99.55%.
Worked. Dividing each oxide by its molar mass and setting phosphorus to 2 gives Al 3.12, Fe 0.03 and F 0.62. With three (OH,F) sites per formula, fluorine fills about 21% of them in the Clonmel material. The sheet’s 1.17% correction checks: 2.79 × 15.999 / (2 × 18.998) = 1.17. Al:P comes out at 1.56 to 1, against 1.5 in the ideal formula.
What that does and does not mean. One analysis shows that natural wavellite can carry fluorine; it does not show how much a given specimen carries, and nothing a collector can do at home measures it. The page reports the difference between the two formulas and leaves it there. Fluorite, the fluorine mineral collectors know, is on fluorite.
Where wavellite is found: Devon, Clonmel and Arkansas
The Distribution field begins many localities, then: the High Down quarry, Filleigh, near South Moulton, Devon, England; Clonmel, Co. Tipperary, Ireland; in Germany, the Rotläufchen mine, Waldgirmes, the Dünsberg near Giessen, Oberscheld near Dillenburg and elsewhere in the Lahr-Dill area (as printed), Hesse, the Wachtelberg at Langenstriegis, Saxony, and the Lichtenberg quarry near Ronneburg, Thuringia; Čerhovice, Czech Republic; large rosettes near Bihain, Belgium; Montebras, Creuse, France.
In the USA and beyond, per the sheet: General Trimble’s mine, Chester Co., Pennsylvania; the Wood mine, Cocke Co., Tennessee; abundant around Avant, as on Dug Hill, Garland Co., and the Mauldin Mountain quarry, near Mt. Ida, Montgomery Co., Arkansas; the Willard mine, Pershing Co., Nevada; fine examples from Llallagua, Potosí and Oruro, Bolivia; the Moculta phosphate quarry and the Iron Monarch quarry, Iron Knob, South Australia.
The shared-locality count. A script compared the place names in the Distribution fields of the three sheets. Four localities appear on both the wavellite and the variscite sheets: Langenstriegis, Saxony; the Lichtenberg area near Ronneburg, Thuringia; Dug Hill near Avant, Garland Co., Arkansas; and the Iron Monarch quarry, Iron Knob, which is also on the turquoise sheet. A green phosphate labelled from one of those four could be either species on the sheets’ evidence, and the ladder above is the place to start. The Devon county page is Devon; the species are indexed at the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.