Abenakiite-(Ce)

Abenakiite-(Ce) (or IMA1991-054) Na26(Ce,Nd,La,Pr,Th,Sm)6-[O|SO2|(CO3)6|(PO4)6|Si6O18] is a mineral of sodium, cerium, neodymium, lanthanum, praseodymium, thorium, samarium, oxygen, sulfur, carbon, phosphorus, and silicon. It is named after the Abenaki, an Algonquian tribe of New England. Its Mohs scale rating is 4 to 5.
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General Information:
 Chemical Formula:
Na26REE6(SiO3)6(PO4)6(CO3)6(S++++O2)O
 Composition:
(Molecular Weight = 2,928.18 gm)
La,Ce,Pr,Nd,Sm,29.51 % RE
Sodium 20.41 % Na
Silicon 5.75 % Si
Phosphorus 6.35 % P 
Carbon 2.46 % C 
Sulfur 1.10 % S 
Oxygen 34.42 % O 
 Empirical Formula:
Na26REE6(SiO3)6(PO4)6(CO3)6(SO2)O
 Environment:
A single crystal embedded in sodalite in a xenolith of sodalite syenite.
 IMA Status:
Approved IMA 1992
 Locality:
TL: Poudrette Quarry, Mont Saint-Hilaire, Rouville County, Quebec, Canada.
 Name Origin:
For the Abenaki Indian tribe, which inhabited the area around Mont Saint-Hilaire.
Physical Properties:
 Cleavage:
[0001] Poor
 Color:
pale brown.
 Density:
3.21
 Diaphaniety:
Transparent
 Habits:
Euhedral Crystals - Occurs as well-formed crystals showing good external form., ,
 Hardness:
4 - Fluorite
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous (Glassy)
 Streak:
white
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