Chamosite
Fe₃²⁺(Fe₂³⁺,Al)(Si₃AlO₁₀)(OH)₈

     Chamosite, a member of the chlorite group, is relatively rare at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color ranges from brown to dark-green.
Luster is vitreous to silky, greasy or dull.
Diaphaneity is translucent to opaque.
Crystal System is monoclinic; C2/m.
Crystal Habits include spherical aggregates and micaceous plates
   to 15mm across.
Cleavage {001} is perfect.
Fracture is uneven.
Hardness is 2 - 2.5
Specific Gravity is approximately 3.2 g/cm³.
Streak is greenish-white to white.
Associated Minerals include albite, anatase, calcite, catapleiite,
   dolomite, fluorapatite, gmelinite, pyrite, quartz, rutile, siderite and
   sphalerite.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1820 after its discovery locality, Chamoson,
    near Saint-Maurice, Canton Valais, Switzerland.

CLASSIFICATION:

REFERENCES:
MinRec 21:303 (1990), Dana 8:1504-1505 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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