Leucosphenite
BaNa₂Ti₂B₂Si₁₀O₃₀

     Mont Saint-Hilaire offers some of the finest and largest crystals of leucosphenite. It is still a rare mineral at MSH. Leucosphenite fluoresces yellowish white under SW.

PHYSICAL CHARACTERISTICS:

Color is usually colorless to very pale blue on smaller crystals;
   and pale blue to grayish blue or white on the larger crystals.
Luster is vitreous to adamantine.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic; C2/m.
Crystal Habits include sharp free-standing crystals to 25mm,
   embedded fine-grained crystals, small embedded round blobs;
   blocky, tabular or prismatic with striated prism faces; short
   pseudohexagonal prism terminated by pinacoids to 6mm.
Cleavage {010} is distinct and {001} is fair.
Fracture is subconchoidal.
Hardness is 6 - 6.5
Specific Gravity is approximately 3.07 g/cm³.
Streak is white.
Associated Minerals include aegirine, albite, amphibole group,
   ancylite, apophyllite series, ashcroftine, bastnäsite, brookite,
   calcite, carletonite, chlorite group, cordylite, donnayite, elpidite,
   epididymite, ewalite, fluorite, galena, harmotome, lorenzenite,
   microcline, molybdenite, monteregianite, narsarsukite, natrolite,
   nepheline, polylithionite, pyrite, pyroxene group, pyrrhotite,
   quartz, sodalite, titanite and wurtzite.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1901 from the Greek leukos, white, plus
   sphena, a wedge, alluding to its color and habit.

CLASSIFICATION:

REFERENCES:
MinRec 21:319 (1990), Dana 8:1541 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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