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 % RE
Sodium 7.79 % Na
Calcium 16.98 % Ca
Fluorine 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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