Pink crystals and aggregates of the rare new mineral manganoeudialyte (IMA 2009-039) from the type locality (Pedra Balao, Pocos de Caldas, Minas Gerais, Brazil) and one of the only five known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Manganoeudialyte
A moderately rare manganese-bearing member of the eudialyte group.
Intro adapted from Wikipedia (CC BY-SA).
Manganoeudialyte is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₁₄Ca₆Mn₃Zr₃[Si₂₆O₇₂(OH)₂](H₂O,Cl,O,OH)₆.
It crystallizes in the hexagonal crystal system (space group R3m). It is a member of the Eudialyte structural group.
Key properties: Mohs hardness 5–6; specific gravity 2.89; White streak; Vitreous luster; optically uniaxial.
IMA symbol Meud, IMA status: approved, named in 2009.
An interstitial phase in nepheline syenite (khibinite).
It is found associated with Eudialyte, K-feldspar, nepheline, aegirine, analcime, sodalite, rinkite, lamprophyllite, astrophyllite, titanite, fluorite, cancrinite.
As a member of the eudialyte group with dominant manganese in the M2 structural sites and silicon dominant in M3 and M4 sites.