:Locality: Kovdor Zheleznyi Mine, Kovdor Massif, Kola, Northern Region, Russian Federation Size: 1.2 × 1 × 1 cm Description: Red to orange labuntsovite-Mg crystals from the type locality. Transparent, well defined and contrasting on the carbonatite matrix. — Photo: Joan Rosell , from rosellminerals.com · CC BY-SA 4.0
Labuntsovite-Mg
Labuntsovite-Mg is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₄K₄Mg₂Ti₈O₄(Si₄O₁₂)₄(OH)₄·10-12H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Labuntsovite structural group.
Key properties: Mohs hardness 5; specific gravity 2.88; Vitreous luster; optically biaxial.
IMA symbol Lab-Mg, IMA status: approved, named in 1998.
Found in cavities within dolomitic carbonatite in an alkaline massif.
It is found associated with Catapleiite, anatase, pyrite, calcite.
Suffix, Mg, refers to the magnesium-dominance in the D site of a member of the labuntsovite subgroup.