Thomasclarkite-(Y)

Thomasclarkite-(Y)

Thomasclarkite-(Y)
General
Category Carbonate mineral
Formula
(repeating unit)
(Na, Ce)(Y, REE)(HCO3)(OH)3·4(H2O)
Crystal system Monoclinic
Crystal class Sphenoidal (2)
H-M symbol: (2)
Space group P2
Identification
Formula mass 375.77 g/mol
Color White, yellow
Crystal habit Blocky crystals, pseudo-tetragonal
Twinning Common on (101)
Cleavage [010] Perfect, [101] Parting
Fracture Uneven
Tenacity Very brittle
Mohs scale hardness 2-3
Luster Vitreous (Glassy)
Streak white
Diaphaneity Translucent to transparent
Specific gravity 2.30
Optical properties pseudouniaxial negative 2V(meas.) ≤ 5°
Refractive index α= 1.40, β= 1.540, γ= 1.540
Birefringence δ = 0.140
Other characteristics Radioactivity 770 Bq/g
References [1][2][3]

Thomasclarkite-(Y) is a rare mineral which was known as UK-93 until 1997, when it was renamed in honour of Thomas H. Clark (1893–1996), McGill University professor. The mineral is one of many rare earth element minerals from Mont Saint-Hilaire. The only reported occurrence is in an alkalic pegmatite dike in an intrusive gabbro-nepheline syenite.

See also

References

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