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Silicate

Fluorapophyllite-(Cs)

CsCa₄(Si₈O₂₀)F(H₂O)₈
Hardness4.5–5
Crystal systemTetragonal
ClassSilicate
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Fluorapophyllite-(Cs)

Fluorapophyllite-(Cs) is an IMA-recognized mineral species in the silicate class, with the chemical formula CsCa₄(Si₈O₂₀)F(H₂O)₈.

It crystallizes in the tetragonal crystal system (space group P4/nnc). It is a member of the Apophyllite structural group.

Key properties: Mohs hardness 4.5–5; specific gravity 2.54; White streak; Vitreous luster.

IMA symbol Fapo-Cs, IMA status: approved, named in 2019.

A hydrothermal mineral.

It is found associated with Quartz, pectolite, baratovite, aegirine, leucosphenite, pyrochlore, neptunite, fluorapophyllite-(K), reedmergnerite.

Suffix indicates the Cs-analogue of fluorapophyllite-(K).

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.