Sepiolite
Mg₄Si₆O₁₅(OH)₂ · 6H₂O

     Sepiolite is moderately rare at Mont Saint-Hilaire, it is difficult to recognize as it is similar to several other species.

PHYSICAL CHARACTERISTICS:

Color is usually white or very pale green.
Luster is dull.
Diaphaneity is opaque.
Crystal System is orthorhombic; Pncn.
Crystal Habits include fibrous aggregates to 5mm.
Cleavage {110} is good (rarely discernible).
Fracture is not observed.
Hardness is 2 - 2.5
Specific Gravity is approximately 2.0 - 2.2 g/cm³.
Streak is white.
Associated Minerals include albite, calcite, diopside, fluorite,
   microcline, monteregianite, pectolite, phlogopite, quartz, richterite,
   sodalite and steacyite. Distinguishing Features: None from other white fibrous species.
Origin: Named in 1847 from the Greek sepion, cuttle-fish bone,
   because of its low density and porous bone like appearance.

CLASSIFICATION:

REFERENCES:
MinRec 21:352 (1990), Dana 8:1560-1561 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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