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Formula: NaNa2(Mg2Al2Li)Si8O22F2
Inosilicate (chain silicate), amphibole
Crystal System: Monoclinic
Specific gravity: 3.14 calculated
Hardness: 6
Colour: Light greenish-blue
Environments:
Fluoro-leakeite is formed by the reaction of alkaline granite with post-magmatic fluids
rich in lithium and fluorine. Associated minerals include cámaraite,
lithium-bearing
riebeckite, aegirine and
astrophyllite
(HOM).
Localities
At the Verkhnee Espe Massif, Akzhaylyautas Mountains, Tarbagatai Range, East Kazakhstan, Kazakhstan, the
granite is strongly altered by late-stage hydrothermal activity, with
enrichment in fluorine,
lithium and rare earth elements. Partial breakdown of
riebeckite,
aegirine, elpidite and
astrophyllite was accompanied by the formation of fluoro-leakeite,
polylithionite, quartz,
rutile and fluorite
(R&M 86.2.165).
At the type locality, Norra Kärr, Gränna, Jönköping, Jönköping County, Sweden, fluoro-leakeite occurs as isolated prismatic
crystals to 2 mm long in an alkaline intrusion that mainly comprises
nepheline syenite
(Mindat).
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