Riebeckite
Na₂Fe₃²⁺Fe₂³⁺(Si₈O₂₂(OH)₂

     Riebeckite, a member of the amphibole group, is fairly rare at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color is usually grayish blue or grayish green.
Luster is vitreous to silky.
Diaphaneity is translucent.
Crystal System is monoclinic; C2/m.
Crystal Habits include matted or radiating flexible fibers to 5cm.
Cleavage {110} is perfect.
Fracture is uneven to subconchoidal.
Hardness is 5 - 6.
Specific Gravity is approximately 3.2 g/cm³.
Streak is gray.
Associated Minerals include albite, apophyllite series, calcite,
   eudialyte and pectolite.
Distinguishing Features: Crystal habit.
Origin: Named in 1888 after Emil Riebeck (1853-1885), German
   explorer who collected the mineral.

CLASSIFICATION:

REFERENCES:
MinRec 21:333 (1990), Dana 8:1361-1364 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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