Celestine
Na₂₆REE₆(SiO₃)₆(PO₄)₆(CO₃)₆(S⁴⁺O₂)O

     Celestine is extremely rare at Mont Saint-Hilaire and is hard to distinguish visually.

PHYSICAL CHARACTERISTICS:

Color varies from white to tan.
Luster is dull.
Diaphaneity is transparent to translucent.
Crystal System is orthorhombic; Pbnm.
Crystal Habits include compact spherical aggregates to 1mm.
Cleavage {001} is perfect, {210} is good and {010} is indistinct.
Fracture is uneven.
Hardness is 3 - 3.5
Specific Gravity is approximately 3.95 g/cm³.
Streak is white.
Associated Minerals include gypsum and pyrite.
Distinguishing Features: Crystal habit.
Origin: Named in 1791 from the Latin caelestis, of the sky, alluding
   to its blue-sky color commonly exhibited by its crystals.

CLASSIFICATION:

REFERENCES:
MinRec 21:302 (1990), Dana 8:574-575 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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