Tetranatrolite or Gonnardite (??)
© Marc Favre
NaAlSi10 · 2H
Do NOT discredit Tetranatrolite yet. A recent paper in the American Mineralogist has called for the discreditation of tetranatrolite in favour of gonnardite. The paper could validate tetranatrolite as gonnardite for all but 4 locations, of which MSH is one. Another paper, soon to be published, on the crystal structure of tetranatrolite seems to validate the species.
Color is white.
Luster is silky to dull.
Diaphaneity is mostly opaque and rarely translucent.
Crystal System is tetragonal; 42
Crystal Habits include small prisms, fibrous sprays and coatings
Cleavage: none observed.
Fracture is (??).
Hardness is 5.
Specific Gravity is approximately 2.3 g/cm
Streak is white.
Associated Minerals include aegirine, amphibole group, analcime,
ancylite-(Ce), microcline, monteregianite-(Y), narsarsukite and
Distinguishing Features: epitactic relationship with natrolite.
Origin: Named in 1980 for the symmetry (tetragonal) and natrolite.
CanMin 18:77-84 (1980), MinRec 21:342 (1990), Dana 8:1679-1680 (1997), AmMin 84:1445-1450 (1999)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE: