Fe22+Al(Si,Al)O5(OH)4
Berthierine, a member of the kaolinite-serpentine group, is found as pseudomorphs at MSH. It is a pseudomorph after a mineral with a layered structure, possibly part of the mica group, minerals mined in Canada.
PHYSICAL CHARACTERISTICS:
Color is usually greenish yellow, yellow or brown.
Luster is dull.
Diaphaneity is translucent.
Crystal System is monoclinic; Cm.
Crystal Habits include sharp pseudo-hexagonal prismatic
pseudomorphs to 5mm terminated with pinacoid.
Cleavage {001} is perfect.
Fracture is uneven.
Hardness is 2 – 2.5.
Specific Gravity is approximately 3.5 g/cm3.
Streak is white.
Associated Minerals include aegirine, allanite, apophyllite series,
calcite, microcline, natrolite, rhodochrosite and titanite.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1832 after Pierre Berthier (1782-1861),
French chemist.
CLASSIFICATION:
Dana System
# 71.1.2c.2
Strunz Classification
# VIII/H.27-70
REFERENCES:
MinRec 21:299 (1990), Dana 8:1423-1424 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH PE AP MX SS MC HF BR SX FR
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