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Niobokupletskite crystals
© Doug Merson

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Home > Mineral Descriptions > Niobokupletskite (TL) - (1 Photo)



Niobokupletskite (Type Locality)
K2Na(Mn,Zn,Fe)7(Nb,Zr,Ti)2Si8O26(OH)4(O,F)

     Niobokupletskite is a new astrophyllite group mineral from Mont Saint-Hilaire. It had been previously reported as "witch's broom astrophyllite" by Wight and Chao in 1986 in Rocks and Minerals. It is brittle and displays pleochroism; X and Y are light orange-yellow and Z is red brown.

PHYSICAL CHARACTERISTICS:

Color ranges from light beige to yellow, light yellow-brown and
   bronze to silvery.
Luster is vitreous.
Diaphaneity: transparent.
Crystal System is triclinic; P1.
Crystal Habits include anhedral to subhedral, platy to tabular epitaxic
   growths; fibrous overgrowth acicular crystals in sheaf-like aggregates.
Cleavage {001} is perfect.
Fracture is uneven to splintery.
Hardness is 3 - 4.
Specific Gravity is approximately 3.46 g/cm3
Streak is white.
Associated Minerals include aegirine, albite, analcime, calcio-ancylite,
   calcite, catapleiite, epididymite, fluorite, genthelvite, kupletskite,
   microcline, natrolite, pyrochlore, rhodochrosite and wurtzite.
Distinguishing Features the crystal habit, color and pleochroism.
Origin: Named in 2000 for its composition, niobo for Nb, and its relation
   to kupletskite in Russia.

CLASSIFICATION:

Dana System
# 69.1.1.8

Strunz Classification
# VIII/G.12-65

REFERENCES:
CanMin 38:627-640 (2000)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
¤¤

AP
¤¤

MX

SS
--

MC
--

HF
--

BR
--

SX
--

FR
--

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