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Formula: Al(OH)3
Hydroxide, perimorph of bayerite,
gibbsite and
nordstrandite
Crystal System: Triclinic
Specific gravity: 2.48 measured, 2.482 calculated
Hardness: 2½ to 3
Streak: White
Colour: White, creamy-white, bluish-white
Solubility: Insoluble in cold mineral acids (Dana)
Environments
Plutonic igneous rocks
Hydrothermal environments
Doyleite is a late-stage hydrothermal mineral lining vugs in veins in
nepheline syenite
(Webmin).
Localities
There are two co-type localities, the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, and the
Francon quarry,
both in Quebec, Canada.
At the Poudrette quarry, doyleite occurs as a late-stage hydrothermal mineral lining vugs in albite-rich veins in a
nepheline syenite pegmatite associated with an intrusive alkalic
gabbro - syenite complex. Associated
minerals include calcite, albite and
pyrite
(HOM, Dana, AM 71.845 ).
At the Francon quarry doyleite occurs sparingly in vugs within silicocarbonate sills intruding
limestone. It is a late stage mineral forming aggregates on
cryolite, weloganite,
strontianite and calcite crystals. Other
associated minerals include albite, baryte,
dresserite, hydrodresserite,
strontiodresserite, quartz,
dawsonite, fluorite,
analcime, halloysite and
montroyalite. Doyleite admixed with
gibbsite
commonly forms perimorphs after
cryolite
(Minrec 37.1.31, AM 71.845).
At the Saint-Amable sill, Varennes & St-Amable, Lajemmerais RCM, Montérégie, Quebec, Canada, doyleite occurs in
miarolitic cavities
in a nepheline syenite sill, associated with
microcline, eudialyte,
yofortierite, astrophyllite,
serandite, aegirine,
cryolite and gibbsite
(HOM, Minrec 37.1.31).
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