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Anthophyllite [abbr. Ath ]

Year of discovery: 1801 (Kjennerudvann, Norway), 1909 (Japan)

Locality list: 116 localities of anthophyllite

• Mg₇Si₈O₂₂(OH)₂
• [][Mg²⁺₂][Mg²⁺₃][Mg²⁺₂][(OH)₂|(Si₄O₁₁)₂]^14-

• Class: Mg-Fe-Mn amphibole subgroup < w(OH,F,Cl)-dominant amphibole group < Amphibole supergroup
• Class: Inosilicate (Double chain) - Hydroxide
• Insoluble in: HCl, HNO₃, H₂SO₄
• Fluorescence: UV excitation (Red)
• One of minerals called Asbestos.

• Polymorph: Cummingtonite (Monoclinic), Proto-anthophyllite (Orthorhombic)

• Mg₂ => Mn₂: Mangano-cummingtonite
• Mg₂ => Ca₂: Tremolite, Actinolite

• Mg => Fe: Ferro-anthophyllite (Series), Grunerite, Proto-ferro-anthophyllite

• MgSi => AlAl: Gedrite (Series)

• Color: Brown-Gray
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Acicular, Prismatic

• Cleavage: Perfect on {210} (2 plane, 120 degree), Imperfect on {010} and {100} (2 planes)
• Hardness: 5.5-6
• Density: 3.2

• System: Orthorhombic
• Group: mmm, Pnma
• Lattice: a=18.6, b=18.0, c=5.3

Synonym: Magnesio-anthophyllite