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Fergusonite-(Y)

Year of discovery: 1827 (Kangeq, Greenland), 1894 (Japan)

Locality list: 160 localities of fergusonite-(Y)

• YNbO₄
• (Y,Ce,Nd)NbO₄
• [Y³⁺][NbO₄]^3-

• Class: Fergusonite group
• Class: Niobate

• Polymorph: β-Fergusonite-(Y) (Monoclinic), Samarskite-(Y) (Monoclinic)

• Y => Ce: Fergusonite-(Ce), β-Fergusonite-(Ce)
• Y => Nd: β-Fergusonite-(Nd)
• Y => Yb: Samarskite-(Yb)
• Y => Ca: Calciosamarskite

• Y₂ => UFe: Ishikawaite, Petscheckite
• Y₂ => YU: Yttrocolumbite-(Y)
• Y₂ => U: Liandratite

• NbO₄ => VO₄: Wakefieldite-(Y)
• NbO₄ => TaO₄: Yttrotantalite-(Y), Formanite-(Y), Iwashiroite-(Y), Takanawaite-(Y)

• Color: Gray, Yellow, Brown
• Tarnish: Black
• Streak: Brown
• Luster: Vitreous
• Diaphaneity: Opaque

• Habit: Prismatic with pyramidal faces

• Cleavage: Poor on {111} (2 planes)
• Hardness: 5.5-6.5
• Density: 5.7

• System: Tetragonal
• Group: 4/m, I4₁/a
• Lattice: a=5.2, c=10.1