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:

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
¤¤¤            —             ¤¤            —             —             —              —               —             —             —  

Legend