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Formula: NaCaBa2La3Sr(CO3)8F2
Anhydrous carbonate containing halogen, cordylite group,
barium-,
lanthanum- and strontium- bearing
mineral
Crystal System: Hexagonal
Specific gravity: 4.34 measured, 4.329 calculated
Hardness: 4
Streak: White
Colour: Colorless, honey-yellow, or pinkish yellow
Luminescence: Non-fluorescent in short wave or long wave UV
Environments:
Carbonatite
Metamorphic environments
Localities
The type locality, Ust'-Biraya, Biraya Fe-REE ore occurrence, Biraya and Bya Rivers confluence area, Vitim
Plateau, Irkutsk Oblast, Russia, comprises a sequence of lens-shaped
carbonatite bodies accompanied by
fenites.
Cordyite-(La) was discovered as colourless to yellow, irregularly shaped, tabular or short-prismatic
hexagonal crystals up to about 3 mm across. They occur in a fine- to medium- grained vein composed mainly of the
carbonates
aragonite–strontianite,
emmonite, strontium-rich
calcite, iron-rich
dolomite, cordylite-(La) and
cordylite-(Ce).
Within the vein, cordylite-(Ce) is more common than
cordylite-(La), with only cordylite-(Ce) occurring as
single grains, while cordylite-(La) may occur as cores within
cordylite-(Ce). Also contained in the vein and in direct
association with cordylite-(La) are baryte,
biraite-(Ce), niobium-rich
chevkinite-(Ce),
fergusonite-(Nd),
ancylite-(Ce), ancylite-(La),
daqingshanite-(Ce),
bastnäsite-(Ce),
hydroxylbastnäsite-(Ce),
carbocernaite,
monazite-(Ce), talc,
thorite, humite,
galena, pyrite and
pyrrhotite. Minerals in the outer zone of the vein near the
fenite include tremolite,
winchite,
ferriallanite-(Ce),
törnebohmite-(Ce),
belkovite, ancylite-(La),
strontianite,
fergusonite-(Ce), zero-valent-dominant light-rare-earth-element
bearing pyrochlore and
nioboaeschynite-(Ce)
(CM 50.5.1281-1290).
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