Ca₂(Fe²⁺,Mg)₅(Si₈O₂₂)(OH)₂

Member of the amphibole group, actinolite is rare at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color ranges from dark green to black.
Luster is vitreous.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic;C2/m.
Crystal Habits include acicular crystals to 5mm.
Cleavage: {001} is perfect.
Fracture is uneven to subconchoidal.
Hardness is 5 – 6.
Specific Gravity is approximately 3.2 g/cm³.
Streak is white.
Associated Minerals include anatase, brookite, calcite, elpidite
and quartz.
Distinguishing Features: Crystal habit.
Origin: Named in 1794 from the Greek aktis, a ray, in allusion
to its common occurrence as radiating needles.

CLASSIFICATION:

REFERENCES:
MinRec 21:294 (1990), DM 8:1346-1350 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH          PE          AP          MX          SS           MC          HF           BR          SX          FR
¤¤¤            —             —             —             —             ¤¤             —             ¤¤             —             —  

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