Trolleite

trolleite

burangaite

augelite

berlinite

Images

Formula: Al4(PO4)3(OH)3
Anhydrous phosphate containing hydroxyl
Specific gravity: 3.10
Hardness: 5½ to 6
Streak: White
Colour: Light green, colourless, bluish green. May be very blue because of mixtures with scorzalite (Mindat)
Solubility: Virtually untouched by acids
Environments

Pegmatites
Metamorphic environments

Trolleite occurs in amphibolite-grade metamorphic rocks (Webmin, HOM).

Localities

At the Buranga pegmatite, Gatumba, Ngororero, Western Province, Rwanda, trolleite is associated with montebrasite, scorzalite, bertossaite, brazilianite, apatite, gatumbaite, samuelsonite and wyllieite (HOM)

At the type locality, the Västanå Iron Mine, Näsum, Bromölla, Skåne County, Sweden, trolleite is associated with pyrophyllite, kyanite, berlinite, attakolite, augelite and lazulite (HOM, Mindat)

At the Champion Mine, White Mountain Peak, White Mountains, Mono county, California, USA trolleite is associated with scorzalite and augelite (HOM, AM 59.974-984)

Alteration

augelite to trolleite, corundum and H2O
3Al2(PO4)(OH)3 to Al4(PO4)3(OH)3 + Al2O3 + 3H2O
(AM 64.1175-1183)

berlinite and H2O to trolleite and phosphoric acid
4Al(PO4) + 3H2O to Al4(PO4)3(OH)3 + H3PO4
(AM 64.1175-1183)

trolleite to augelite and berlinite
Al4(PO4)3(OH)3 to Al2(PO4)(OH)3 + 2Al(PO4)
(AM 64.1175-1183)

trolleite to berlinite, corundum and H2O
2Al4(PO4)3(OH)3 to 6Al(PO4) + Al2O3 + 3H2O
(AM 64.1175-1183)

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