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Bismutotantalite

Year of discovery: 1929 (Gamba Hill, Uganda), 1963 (Japan)

Locality list: 2 localities of bismutotantalite

• BiTaO₄
• Bi(Ta,Nb)O₄
• [Bi³⁺][TaO₄]^3-

• Class: Stibiocolumbite group
• Class: Tantalate
• Insoluble in: HCl

• Bi => Sb: Stibiotantalite
• Bi => Y: Yttrotantalite-(Y), Formanite-(Y), Iwashiroite-(Y), Takanawaite-(Y)

• Bi₂ => MnSn; Wodginite
• Bi₂ => FeSn; Ferrowodginite
• Bi₂ => MnTi; Titanowodginite

• TaO₄ => NbO₄: Bismutocolumbite

• Color: Light brown-Black
• Streak: Yellowish brown
• Luster: Sub-Metallic
• Diaphaneity: Translucent-Opaque

• Cleavage: Good on {010} (1 planes), Distinct on {101}{100} (3 planes)
• Hardness: 5-5.5
• Density: 8.5

• System: Orthorhombic
• Group: mmm, Pcmn
• Lattice: a=5.6, b=11.8, c=5.0

Etymology: Bi-bearing Tantalite