Augelite

phosphate

siderite

Formula:Al2(PO4)(OH)3
Anhydrous phosphate containing hydroxyl
Specific gravity: 2.696
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).

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