Formula: Na15Ca6Fe3Zr3Si(Si25O73)(O,OH,H2O)3(Cl,OH)2
Cyclosilicate (ring silicate) containing zirconium, Zr
Specific gravity: 2.74 - 3.1
Hardness: 5 to 6
Streak: White to pale pink
Colour: Carmine-red, orange-red, orange, pink, cherry-red, brownish-red, yellowish-brown, brown, yellow, violet, green.
Solubility: Gelatinises with acids (Dana)

Plutonic igneous environments

Eudialyte occurs in igneous rocks such as nepheline syenite and granite, and their associated pegmatites (Webmin, Dana, HOM). It may alter to catapleiite, zircon, feldspar, aegirine, analcime and clay minerals (Dana). Associated minerals include microcline, nepheline, aegirine, lamprophyllite, lorenzenite, murmanite, arfvedsonite, sodalite, aenigmatite, rinkite, lavenite, titanite and titanian magnetite (HOM).

The type locality is the Kangerluarsuk Fjord, Ilímaussaq complex, Narsaq, Kujalleq, Greenland, Denmark.

At the Palitra pegmatite, Lovozero Massif, Kola Peninsula, Russia, eudialyte is associated with aegirine, arfvedsonite, lorenzenite, microcline, nepheline and villiaumite (Min Rec 36.5.404).

Common impurities: K,Mg,Sr,TR,Ti,Nb,Al,F,P,S

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