Orthoclase
KAlSi₃O₈

     Orthoclase, a member of the feldspars has been recently identified at Mont Saint-Hilaire. More info to follow.

PHYSICAL CHARACTERISTICS:

Color is usually (??).
Luster is vitreous.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic; C2/m.
Crystal Habits include (??).
Cleavage {001} is perfect with {010} less perfect.
Fracture is subconchoidal to uneven.
Hardness is 6 - 6.5
Specific Gravity is approximately 2.59 g/cm³.
Streak is (??).
Associated Minerals include (??).
Distinguishing Features: (??).
Origin: Named in 1823 from the Greek orthos, right, and kalo, I cleave,
   in allusion to the mineral's perpendicular cleavages.

CLASSIFICATION:

REFERENCES:
Dana 8:1600-1602 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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