Biraite-(Ce)

biraite-(Ce)

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Formula: Ce2Fe2+(CO3)(Si2O7)
Sorosilicate (Si2O7 groups), biraite group
Crystal System: Monoclinic
Specific gravity: 4.76 calculated
Hardness: 5
Streak: White
Colour: Brown
Solubility: Soluble in strong acids such as hydrochloric and nitric acids
Weakly RADIOACTIVE
Environments

Metamorphic environments
Carbonatites

Localities

At Mochalin Log, Kyshtym, Chelyabinsk Oblast, Russia, biraite-(La), together with alexkuznetsovite-(La) and alexkuznetsovite-(Ce), was discovered in polymineralic nodules as brown to dark brown anhedral grains up to 0.2 × 1.2 mm2 embedded in granular aggregates consisting of different rare earth minerals, including allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), fluorbritholite-(Ce), perbøeite-(Ce), perbøetite-(La), percleveite-(Ce), percleveite-(La), törnebohmite-(Ce) and törnebohmite-(La) (MM 84.4.593–607).

At the type locality, Ust'-Biraya, Biraya Fe-REE ore occurrence, Biraya and Bya Rivers confluence area, Vitim Plateau, Irkutsk Oblast, Russia, biraite-(Ce) has been found In a vein that cuts fenite fragments in a carbonatite. Associated minerals include cordylite-(Ce), cordylite-(La), aragonite, strontianite, strontium- and iron- bearing dolomite, ancylite-(Ce), ancylite-(La), hydroxylbastnäsite-(Ce), daqingshanite-(Ce), tremolite, winchite, ferriallanite-(Ce), törnebohmite-(Ce), cerite, chevkinite-(Ce), belkovite, humite, fergusonite-(Ce), fergusonite-(Nd), pyrochlore, baryte, monazite-(Ce) and other unknown minerals.
Biraite-(Ce) occurs as irregular to well-shaped brown, semi-transparent, vitreous grains from 0.1 to 3 mm in size (EJM 17.5.715–721, HOM).

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