Gjerdingenite-Na (Type Locality)
(K,Ba,Na)(Ti,Nb)(Si,Al)₂(O,OH)₇ · H₂O

     Gjerdingenite-Na, a member of the labuntsovite-nenadkevichite group, has been recently as new species from Mont Saint-Hilaire material. It's designation is IMA 2005-030. It had been originally been identified as UK 19(1) in 1969 in Peter Tarassoff's collection. Large quantities of this material were available when the pegmatite was exposed, and specimens were undoubtedly labelled as nenadkevichite. Furthermore, it has been identified as vuoriyarvite-K before being treated as a new type locality for MSH.

PHYSICAL CHARACTERISTICS:

Color is colorless to pale pink, whitish pink or cream colored.
Luster is vitreous.
Diaphaneity is transparent for the small crystals and translucent to opaque for the larger crystals.
Crystal System is monoclinic; C2/m.
Crystal Habits include singles, radiating clusters of prisms; epitactic
   overgrowth on elpidite.
Cleavage is not observed.
Fracture uneven.
Hardness is 5.
Specific Gravity is approximately 2.69g/cm³
Streak is white.
Associated Minerals include albite, aegirine, analcime, epistolite,
   eudialyte group, microcline, natrolite, polylithionite after vuonnemite.
Other Properties brittle.
Origin being published at this time.

CLASSIFICATION:

REFERENCES:
CanMin 45: 529-539 (2007).

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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