Formula: Al(PO4)
Anhydrous normal phosphate
Specific gravity: 2.64 to 2.66
Hardness: 6½
Streak: White
Colour: Colourless, greyish or pale pink; colourless in transmitted light.
Solubility: Readily soluble in alkalies; virtually insoluble in cold acids.

Metamorphic environments
Hydrothermal environments

Berlinite is a rare high-temperature hydrothermal or metasomatic mineral. Often found in caves after guano fires (Webmin, HOM).
It is isostructural with quartz, which is a tectosilicate (framework silicate). Berlinite inverts at 583° to a polymorph isotypic with β-SiO2 (Mindat)
In granite pegmatites associated minerals include augelite, attakolite, kyanite, pyrophyllite, scorzalite, lazulite, gatumbaite, burangaite, amblygonite, phosphosiderite, purpurite, apatite, muscovite, quartz and hematite (HOM).

At Paddy's River mine, Australia, berlinite is associated with alunite, aragonite, collophane (variety of apatite), crandallite, francoanellite, gypsum, huntite, hydromagnesite, leucophosphite, nesquehonite, niter and nitrocalcite (HOM).

At the type locality, the Västanå Iron Mine, Näsum, Bromölla, Skåne County, Sweden, berlinite is associated with augelite and attakolite (Mindat).

Common impurities: Fe,Si

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