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Formula: Li2SrAl4(PO4)4(OH)4
Anhydrous phosphate containing hydroxyl, palermoite group, forms a series with
bertossaite,
lithium- and strontium- bearing
mineral
Crystal System: Orthorhombic
Specific gravity: 3.22 measured
Hardness: 5½
Streak: White
Colour: Colourless, white, pale pink
Luminescence: Fluoresces white in direct X-ray beam (Mindat)
Environments
Pegmatites
Hydrothermal environments
Localities
At the Carmo di Loano Mt., Toirano, Savona Province, Liguria, Italy, palermoite occurs near
quartz veins in sandstones and
conglomerates subjected to
greenschist metamorphism. Associated minerals include
lazulite, goyazite and
brazilianite
(HOM).
The type locality, the Palermo No. 1 Mine, Groton, Grafton county, New Hampshire, USA, is a complex zoned
granite pegmatite.
Palermoite occurs here in two paragenetic settings.
Paragenesis 1 consists of cavities in quartz veins extending from the
pegmatite core into a first intermediate zone. Palermoite
can be sprinkled randomly on the surfaces of quartz crystals lining voids in the
vein. Associated species are few and include rare white pseudocubic goyazite to
several millimeters and milky-white simple carbonate-rich fluorapatite
crystals to 1 cm.
Paragenesis 2 consists of siderite and
whitlockite replacements of
triphylite in the first intermediate zone around the core.
Siderite occurs as pale brown to amber-brown grains to 1 cm, sometimes coated
with resinous olive-grey diadochite botryoids, much smaller than 1 mm.
Whitlockite occurs as white masses interspersed with
quartz and siderite;
secondary whitlockite
crystals, to several millimeters, occur in vugs in siderite.
Other early minerals in this paragenesis include doubly terminated quartz,
compact kaolinite, brown
childrenite crystals and white carbonate-rich
fluorapatite.
Later minerals include palermoite, goyazite,
crandallite, limonite,
mitridatite, bjarebyite,
goedkenite and
hydroxylherderite.
Palermoite associates include pearly white thin platelets of goyazite,
to 1 mm, that occur as interpenetrating intergrowths on palermoite and
siderite; crandallite occurs as
white to tan crystallised globules, to 1 mm, as a late-stage growth on palermoite;
bjarebyite was also observed associated with palermoite.
Goedkenite appears to be distributed throughout paragenesis 2, but most
palermoite shows no goedkenite in association; when it does occur,
goedkenite is almost universally epitaxial to palermoite or
goyazite, as colourless wedge-shaped tablets
(R&M 77.4.240-241, R&M 97.3.283-287).
Palermoite crystals are typically transparent and colourless, 1 to 2 mm in size, and usually euhedral.
Palermoite commonly occurs in isolated crystals, although two crystals in parallel growth are not uncommon
(R&M 77.3.173).
Other reported associations at this locality include beraunite, and
brazilianite
(HOM); and a relatively new mineral, natropalermoite, approved
in 2013
(MM 81.833-840).
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