Fluor-tsilaisite
Fluor-tsilaisite is an IMA-recognized mineral species in the silicate class, with the chemical formula NaMn²⁺₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃F.
It crystallizes in the hexagonal crystal system (space group R3m). It is a member of the Tourmaline structural group.
Key properties: Mohs hardness 7; specific gravity 3.134; White streak; Vitreous luster; optically uniaxial.
IMA symbol Ftl, IMA status: approved, named in 2012.
Occurs as portion of a color-zoned tourmaline crystal in an aplitic dike of an LCT-type (lithium-, cesium- and tantalum-enriched) pegmatite body.
It is found associated with Quartz, K-feldspar, plagioclase, elbaite, schorl, fluor-elbaite, tsilaisite.
Represents the fluorine-dominant analog of tsilaisite.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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