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Allanite-(Y)

Year of discovery: 1810 (World), 1999 (Japan)

Locality list: 4 localities of allanite-(Y)

• CaYAl₂FeSi₃O₁₂(OH)
• (Ca)(Y,Ce)Al₂FeSi₃O₁₂(OH)
• [Ca²⁺Y³⁺][Al³⁺₂Fe²⁺][OH|O|SiO₄|Si₂O₇]^13-

• Class: Allanite series < Allanite group < Epidote supergroup
• Class: Sorosilicate - Nesosilicate - Oxide - Hydroxide
• Radioactive: Weak

• Y => Ce: Allanite-(Ce)
• Y => Nd: Allanite-(Nd)
• Y => La: Allanite-(La)
• Y => Ca: Epidote
• Y => Pb: Epidote-(Pb)
• Y => Sr: Epidote-(Sr)

• Color: Black-Brown
• Tarnish: Dull luster
• Streak: Gray
• Luster: Resinous
• Diaphaneity: Opaque

• Cleavage: Imperfect on {001} (1 plane), Poor on {100} and {110} (2 planes)
• Hardness: 5.5-6.5
• Density: 3.8

• System: Monoclinic
• Lattice: a=9.0, b=5.8, c=10.2, β=115.0