Siderophyllite, a member of the mica group, occurs rarely at MSH.
PHYSICAL CHARACTERISTICS:
Color is usually dark green to black.
Luster is vitreous.
Diaphaneity is transparent to opaque.
Crystal System is monoclinic, 2/
Crystal Habits include foliated masses and pseudo-hexagonal prisms.
Cleavage {001} is perfect.
Fracture is not apparent due to cleavage.
Hardness is 2.5
Specific Gravity is approximately 3.0 g/cm
Streak is greenish-gray.
Associated Minerals include annite and biotite group.
Distinguishing Features: Crystal habits.
Origin: Named in 1880 from the Greek sideros, iron, plus phyllon, leaf,
alluding to its composition and perfect basal cleavage.
CLASSIFICATION:
Dana System
# 71.2.2b.5
Strunz Classification
# VIII/H.11-90
REFERENCES:
MinRec 21:338 (1990), Dana 8:1461-1462 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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