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Hellandite-(Y)

Year of discovery: 1903 (Lindvikskollen quarry, Norway), 1987 (Japan)

Locality list: 3 localities of hellandite-(Y)

• Ca₄Y₂AlB₄Si₄O₂₂(OH)₂
• (Ca,Y)₆(Al,Fe)B₄Si₄O₂₂(OH)₂
• [Ca²⁺₃REE³⁺][Y³⁺)₂][Al³⁺][][(OH)₂|(B₂Si₂O₁₁)₂]^18-

• Class: Hellandite group
• Class: Phyllo-Borosilicate - Hydroxide
• Soluble in: HCl
• Radioactive: Weak

• Y => Ce: Hellandite-(Ce)

• Color: Yellow, Green, Brown
• Luster: Vitreous
• Diaphaneity: Translucent

• Cleavage: Poor on {100} and {001} (2 planes)
• Hardness: 5.5-6
• Density: 3.7

• System: Monoclinic
• Group: 2/m, P2/a
• Lattice: a=19.0, b=4.7, c=10.3, β=111.4