Formula: (Y,U)(Ti,Nb)2(O,OH)6 (?)
Multiple oxide, a metamict member of the euxenite group,
yttrium-bearing mineral
Specific gravity: 4.60
Hardness: 5½
Streak: Reddish brown
Colour: Black to dark brown
RADIOACTIVE
Environments
Plutonic igneous environments
Pegmatites
Localities
At the Ushio deposit, Okuchi mine, Okuchi City, Kagoshima Prefecture, Japan, kobeite
is associated with plagioclase,
allanite, zircon,
fergusonite, magnetite,
ilmenite and pyrite
(HOM).
At the type locality, Shiraishi-yama, Kobe, Kyōtango City, Kyoto Prefecture, Japan, kobeite occurs in a
granite pegmatite
associated with parisite, zircon,
monazite, chevkinite,
xenotime, biotite,
albite, smoky and white quartz,
anatase, allanite and
muscovite
(AM36.925, HOM).
At Weheka-Paringa Road bridge area, Paringa River, Westland District, West Coast Region, South Island, New Zealand, a
kobeite-bearing cobble, 75 millimetres in diameter, was collected while panning sands and gravels in the river.
The kobeite occurs as very dark brown prismatic crystals with a sheaf-like or radiating arrangement. The matrix
consists of a coarse aggregate of oligoclase and
microcline; very rare quartz,
epidote, muscovite and
chlorite complete the mineral assemblage
(AM 42.342-353).
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