Abenakiite-(Ce) (Type Locality)
Na₂₆REE₆(SiO₃)₆(PO₄)₆(CO₃)₆(S⁴⁺O₂)O

     A single crystal from an unknown phase was discovered in a xenolith of sodalite syenite (UK85). It is coated by an unidentified rhabdophane-group mineral.

     More than 72 minerals have been recorded from the same xenolith. Abenakiite-(Ce), is a late-stage phase, possibly arising from a metasomatic event associated with emplacement of the nepheline syenite.

PHYSICAL CHARACTERISTICS:

Color is predominantly pale brown.
Luster is vitreous.
Diaphaneity is translucent.
Crystal System is hexagonal; R3.
Crystal Habits a single ellipsoidal 2mm X 1mm.
Cleavage: {001} is poor.
Fracture is conchoidal.
Hardness is > 4.
Specific Gravity is approximately 3.27 g/cm³.
Streak is white.
Associated Minerals include aegirine, eudialyte, mangan-neptunite,
   polylithionite, sérandite and steenstrupine-(Ce).
Distinguishing Features: Brittle. No fluorescence observed.
Origin: Named for the Abenaki tribe, which inhabited the area around
   Mont Saint-Hilaire. Described in 1994.

CLASSIFICATION:

REFERENCES:
CanMin 32:843-854 (1994), Dana 8:1264-1265 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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