General Information:
Chemical Formula:Na(REExCa1-x)(REEyCa1-y)F6 where (x ne y)
Composition:(Molecular Weight = 295.08 gm)La,Ce,Pr,Nd,Sm,36.60 %
RESodium 7.79 %
NaCalcium 16.98 %
CaFluorine 38.63 %
F Empirical Formula: NaREE0.5Ca0.5REE0.25Ca0.75F6
Environment:In a Precambrian peralkaline granitic complex.
IMA Status:Approved IMA
Locality:The Strange Lake rare-earth-element deposit, about 250 km northeast of Schefferville, Quebec, on the Quebec-Labrador border, Canada.
Name Origin:For Dr. Ihor Stephan Zajac (1935- ), the geologist who lead the exploration group that discovered the Strange Lake deposit and who first reconized the mineral.
Physical Properties: Cleavage:None
Color:colorless, pale pink, or orange.
Density:4.44 - 4.55, Average = 4.49
Diaphaniety:Transparent
Habits:Granular - Generally occurs as anhedral to subhedral crystals in matrix., ,
Hardness:3.5 - Copper Penny
Luminescence:Non-fluorescent.
Luster:Vitreous (Glassy)
Streak:white
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