Kupletskite
(K,Na)₃(Mn,Fe⁺²)₇(Ti,Nb)₂Si₈O₂₄(O,OH)₇

     Kupletskite, the potassium-iron dominant member of the astrophyllite group, is uncommon at MSH. It cannot be distinguished visually from astrophyllite.

PHYSICAL CHARACTERISTICS:

Color is usually bronze-yellow.
Luster is vitreous to submetallic.
Diaphaneity is transparent to opaque.
Crystal System is triclinic; P1.
Crystal Habits include tabular crystals to 3mm, acicular crystals,
   and micaceous or fibrous masses.
Cleavage {001} is perfect and {100} is poor.
Fracture is uneven.
Hardness is approximately 4.
Specific Gravity is approximately 3.2 g/cm³.
Streak is brown.
Associated Minerals include aegirine, albite, ancylite, arfvedsonite,
   calcite, eudialyte, fluorite, microcline and natrolite.
Distinguishing Features: Crystal habit.
Origin: Named in 1956 after Boris Mikhailovich Kupletski (1894-1965)
   and Elsa Maxilianovna Bonshedt-Kupletskaya (1897-1974),
   Russian geologists.

CLASSIFICATION:

REFERENCES:
MinRec 21:315 (1990), Dana 8:1383 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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