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Annite
KFe32+(AlSi3O10)(OH,F)2

     A member of the mica group, annite is indistinguishable from biotite and is uncommon at MSH.

PHYSICAL CHARACTERISTICS:

Color is usually black or dark green.
Luster is vitreous to submetallic.
Diaphaneity is transparent to opaque.
Crystal System is monoclinic; C2/m.
Crystal Habits include large well-formed pseudohexagonal prisms
    to 12cm across and 15cm long.
Cleavage: {001} is perfect.
Fracture is uneven.
Hardness is 2 - 3.
Specific Gravity is approximately 3.3 g/cm3.
Streak is white.
Associated Minerals include microcline.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1868 after its discovery locality at Cape Ann,
    Essex county, Massachusetts, U.S.A..

CLASSIFICATION:

Dana System
# 71.2.2b.3

Strunz Classification
# VIII/H.11-50

REFERENCES:
MinRec 21:296 (1990), Dana 8:1461 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
¤¤

AP
--

MX
--

SS
¤¤

MC
--

HF
--

BR
--

SX
¤¤

FR
--

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