Fluoro-magnesio-arfvedsonite
NaNa₂Mg₄Fe³⁺(F,OH)₂Si₈O₂₂

     A brand new addition for mont Saint-Hilaire in 2006. It is the fluorine-dominant member of magnesio-arfvedsonite. More information will be published as it becomes available.

PHYSICAL CHARACTERISTICS:

Color is predominantly dark grey to greyish black.
Luster is vitreous.
Diaphaneity is translucent.
Crystal System is monoclinic; C2m.
Crystal Habits (??).
Cleavage: {001} is perfect.
Fracture is conchoidal.
Hardness is 5.5
Specific Gravity is approximately 3.09 g/cm³.
Streak is pale grey.
Associated Minerals include (??).
Distinguishing Features: Brittle. No fluorescence observed.
Origin: Named in 1998 for its relation to arfvedsonite and its fluorine and magnesium content.

CLASSIFICATION:

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

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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