Pirssonite
Na₂Ca(CO₃)₂ · 2H₂O

     Pirssonite is another rare species from MSH.

PHYSICAL CHARACTERISTICS:

Color is usually colorless to yellow.
Luster is vitreous.
Diaphaneity is transparent.
Crystal System is orthorhombic; Fdd2.
Crystal Habits include prismatic crystals and diamond shaped
   cross-sections.
Cleavage none.
Fracture is conchoidal.
Hardness is 3 - 3.5
Specific Gravity is approximately 2.35 g/cm³.
Streak is white.
Associated Minerals include analcime, calcite, feldspar group,
   galena, halite and kogarkoite.
Distinguishing Features: Crystal habits.
Origin: Named in 1896 after Louis Valentine Pirsson (1860-1919),
   American professor of geology.

CLASSIFICATION:

REFERENCES:
Dana 8:465 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

Legend