Natrolite
[Na₂Al₂Si₃O₁₀ · 2H₂O]

     Natrolite is another widespread species at MSH. It occurs in almost every rock environment and is associated with many different species.

PHYSICAL CHARACTERISTICS:

Color is usually colorless or white, rarely pale pink or very pale bluish gray
Luster is vitreous to silky, greasy or dull.
Diaphaneity is transparent to translucent, opaque on white and fibrous
   crystals.
Crystal System is orthorhombic; Fdd2.
Crystal Habits include the pseudotetragonal prisms, fibrous aggregates
   to 10cm, and crystalline masses.
Cleavage {110} perfect and {010} imperfect.
Fracture is uneven.
Hardness is 5 - 5.5.
Specific Gravity is approximately 2.25 g/cm³.
Streak is white.
Associated Minerals include aegirine, albite, amphibole group, analcime,
   ancylite-(Ce), astrophyllite, bastnäsite, calcite, catapleiite, chlorite group,
   cordylite, dolomite, elpidite, epididymite, eudialyte, fluorite, gonnardite,
   mangan-neptunite, nepheline, polylithionite, pyrophanite, rhodochrosite,
   sérandite and siderite.
Distinguishing Features: crystal habit and forms.
Origin: Named in 1803 from the Greek natrium, soda, referring to its
   sodium content.

CLASSIFICATION:

REFERENCES:
MinRec 21:325 (1990), Dana 8:1677-1679 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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