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Formula:Al2(PO4)(OH)3
Anhydrous phosphate containing hydroxyl
Crystal System: Monoclinic
Specific gravity: 2.696 measured, 2.704 calculated
Hardness: 4½ to 5
Streak: White
Colour: White, colourless, pale yellow, light green, rarely blue or pink; colourless in transmitted light.
Solubility: Slowly soluble in hot concentrated hydrochloric acid.
Environments
Metamorphic environments
Hydrothermal environments
Augelite is formed by metamorphism of phosphate-bearing rocks in aluminium-rich sediments, and also in some
high-temperature hydrothermal ore deposits (Webmin, HOM). Associated minerals include
fluorapatite, pyrite and
siderite (Mindat).
At Oruro, Bolivia, Bolivia, a mass of augelite, arsenopyrite,
quartz, pyrite, and
stannite crystals has been found coating a matrix of massive
quartz, pyrite and
tetrahedrite (AM 20.664-668).
At the Socovon mine, Oruro, Bolivia, augelite has been found with with
arsenopyrite, stannite,
pyrite and quartz (Dana).
At the Machacamarca Mine, Cornelio Saavedra Province, Potosí, Bolivia, augelite has been found associated with
bournonite and pyrite
(AM 20.664-668).
At the silver mines of Tatasí, Sud Chichas Province, Potosí, Bolivia, augelite is associated with
pyrite, siderite,
gypsum, calcite,
pyrophyllite and sphalerite in
the jamesonite "feather" ore (AM 20.664-668).
At Mudo Nuevo, Peru, large (up to 5 cm) crystals of augelite on quartz druses
have been found (MinRec 42.2.141).
At the type locality, the Västanå Iron Mine, Näsum, Bromölla, Skåne County, Sweden, augelite is associated with
attakolite, svanbergite,
lazulite, hematite,
trolleite and berlinite
(Mindat, HOM).
At Mbale, Uganda, augelite occurs with amblygonite (Dana).
At the Mono County mine, California, USA, augelite was discovered in the
andalusite orebody; it occurs as a hydrothermal mineral deposited from
hydrothermal solutions that acted upon the andalusite subsequent to
the formation of andalusite, corundum,
diaspore, topaz and other minerals.
The augelite is directly associated and intergrown with lazulite,
rutile, baryte,
pyrophyllite, muscovite,
alunite, and quartz
(AM 20.664-668).
At the Chickering Mine, Walpole, Cheshire County, New Hampshire, USA, augelite crystals occur in
siderite and quartz vugs in an
apatite matrix (R&M 90.5.414).
Alteration
augelite to berlinite,
corundum and H2O
2Al2(PO4)(OH)3 to 2Al(PO4) + Al2O3 + 3H2O
(AM 64.1175-1183)
augelite to trolleite, corundum and
H2O
3Al2(PO4)(OH)3 to Al4(PO4)3(OH)3 +
Al2O3 + 3H2O
(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 augelite and berlinite
Al4(PO4)3(OH)3 to Al2(PO4)(OH)3 + 2Al(PO4)
(AM 64.1175-1183)
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