Fluor-dravite
Fluor-dravite is an IMA-recognized mineral species in the silicate class, with the chemical formula NaMg₃Al₆(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 3.12; Pale brown streak; Vitreous luster; optically uniaxial.
IMA symbol Fdrv, IMA status: approved, named in 2009.
Formed near the contact between a granitic pegmatite and country rock.
It is found associated with K-feldspar, plagioclase, quartz, beryl, muscovite, garnet, biotite, fluorite.
As a dravite with dominant fluorine in the W site.
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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