Phlogopite
KMg₃Si₃AlO₁₀(F,OH)₂

     Phlogopite, a member of the mica group is relatively uncommon at MSH. It is much rarer than the other members of the mica group.

PHYSICAL CHARACTERISTICS:

Color is usually brown; tan to gray.
Luster is vitreous to pearly.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic; C2/m.
Crystal Habits include well-formed pseudohexagonal crystals to 5mm
   and as small embedded flakes.
Cleavage {001} is perfect.
Fracture is not apparent due to cleavage.
Hardness is 2 - 2.5
Specific Gravity is approximately 2.9 g/cm³.
Streak is white.
Associated Minerals include albite, amphibole group, ancylite,
   calcite and fluorite.
Distinguishing Features: Crystal habit and cleavage.
Origin: Named in 1841 from the Greek phlogopos, fire-like, alluding
   to its common reddish tinge.

CLASSIFICATION:

REFERENCES:
MinRec 21:330 (1990), Dana 8:1456-1458 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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