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Pectolite (Photo) [abbr. Pct ]

Year of discovery: 1828 (Monzoni Mountains, Italy, and Sano, Monte Baldo, Italy), 1932 (Japan)

Locality list: 59 localities of pectolite

• NaCa₂Si₃O₈(OH)
• [Na⁺][Ca²⁺₂][HSi₃O₉]^5-

• Class: Wollastonite group < 3-periodic < Pyroxenoid
• Class: Inosilicate (Single chain) - Hydroxide
• Soluble in: HCl (Gel residue)
• Fluorescence: UV excitation (Green-Orange-Pink), Triboluminescence

• Na => Li: Murakamiite

• NaH => Ca: Wollastonite

• Ca => Mn: Sérandite (Serandite) (Series)

• NaCa => Sc: Cascandite

• Color: Colorless, White
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Acicular, Fibrous, Tabular
• Aggregate: Perpendicular to the vein

• Cleavage: Perfect on {100} and {001} (2 planes)
• Hardness: 4.5-5
• Density: 2.9

• System: Triclinic (Aabc), Monoclinic (A2abc) (Layer-stacking polytype)
• Group: (-1), P(-1)
• Lattice: a=8.0, b=7.0, c=7.0, α=90.5, β=95.2, γ=102.5

Etymology: Pektos (Condensed) in Greek