[ Top ] [ Japanese ]

Ferro-actinolite (Photo) [abbr. Fac ]

Year of discovery: 1946 (World), 1949 (Japan)

Locality list: 22 localities of ferro-actinolite

• Ca₂Fe₅Si₈O₂₂(OH)₂
• Ca₂(Fe,Mg)₅Si₈O₂₂(OH)₂
• [][Ca²⁺₂][Fe²⁺₅][(OH)₂|Si₈O₂₂]^14-

• Class: Ca amphibole subgroup < w(OH,F,Cl)-dominant amphibole group < Amphibole supergroup
• Class: Inosilicate (Double chain) - Hydroxide

• Mg/(Mg+Fe)=0.5-0.9: Actinolite (Series)
• Fe => Mg: Tremolite (Series)

• Ca => Fe: Ferro-anthophyllite, Grunerite, Proto-ferro-anthophyllite
• Ca => Mn: Mangano-grunerite, Proto-ferro-suenoite
• Ca => Na: Riebeckite

• Ca₂ => Na₂Ca: Ferro-richterite

• Si => Al: Ferro-ferri-hornblende

• CaFe => NaAl: Ferro-winchite
• CaFe => NaFe: Ferro-ferri-winchite

• CaSi => Na₂Al: Ferro-ferri-katophorite

• FeSi => Al₂: Ferro-hornblende

• Si₂ => Al₂: Ferro-ferri-tschermakite

• Fe₂Si₂ => Al₄: Ferro-tschermakite

• Color: Dark green
• Streak: Pale green
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Acicular, Prismatic

• Cleavage: Distinct on {110} (2 planes, 120 degree)
• Hardness: 5-6
• Density: 3.0

• System: Monoclinic
• Group: 2/m, C2/m
• Lattice: a=9.9, b=18.2, c=5.3, β=105.0

Etymology: Aktis (ray) in Greek