crystals of tourmaline var. liddicoatite, crystals of feldspar var. microcline : Ampanodiana South pegmatite, Tetezantsio-Andoabatokely Pegmatite Field, Andremb — Photo: Parent Géry · CC0
Fluor-liddicoatite
The calcium end-member of the elbaite tourmaline series — rare, and named for gemologist Richard Liddicoat.
Intro adapted from Wikipedia (CC BY-SA).
Fluor-liddicoatite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca(Li₂Al)Al₆(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 7.5; specific gravity 3.02; typically pink or green or brown or blue; white streak; vitreous luster; refractive index 1.629; optically uniaxial.
IMA symbol Fld, IMA status: approved, named in 1976.
Collections: Gemstones, Collector Favorites.