Fluorapophyllite-(Cs)

fluorapophyllite-(Cs)

pectolite

baratovite

leucosphenite

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Formula: Cs4Si8O20F.8H2O
Phyllosilicate (sheet silicate), cesium-bearing mineral
Crystal System: Tetragonal
Specific gravity: 2.54measured, 2.513 calculated
Hardness: 4½ to 5
Streak: White
Colour: Colourless
Environments

Hydrothermal environments

Fluorapophyllite-(Cs) was approved as a new mineral in 2019. Historically all the apophyllite group minerals were reported simply as "apophyllite", and indeed it requires analysis to differentiate between them, so there is comparatively little information about the individual members of the group, except in recent times. Please check the apophyllite page for more information.

Localities

At the type locality, the Dara-i-Pioz Glacier, Districts of Republican Subordination, Tajikistan, fluorapophyllite-(Cs) is an apophyllite group mineral from the moraine. It was found in a quartz-pectolite aggregate in quartzolite boulders. Associated minerals include quartz, pectolite, baratovite, aegirine, leucosphenite, pyrochlore, neptunite, fluorapophyllite-(K) and reedmergnerite (CM 57.965-971).

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