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Silicate

Ferro-tschermakite

Ca₂(Fe²⁺₃Al₂)(Si₆Al₂)O₂₂(OH)₂
Hardness5–6
Crystal systemMonoclinic
ClassSilicate
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Ferro-tschermakite

Ferro-tschermakite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₂(Fe²⁺₃Al₂)(Si₆Al₂)O₂₂(OH)₂.

It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Amphibole structural group.

Key properties: Mohs hardness 5–6; specific gravity 3.32–3.35; [Vitreous.] luster; optically biaxial.

IMA symbol Fts, IMA status: approved, named in 2016.

A product of medium- to high-pressure metamorphism of highly aluminous rocks, producing schists, gneisses, or amphibolites; from differentiated mafic plutonic igneous rocks.

It is found associated with Almandine, chlorite, biotite, muscovite, quartz, anorthite, apatite (metamorphic).

The name refers to ferrous iron in its composition and relation to tschermakite.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more F minerals or help write this entry.