Eifelite

eifelite

roedderite

tridymite

pseudobrookite

Images

Formula: KNa₂(MgNa)(Mg₃Si₁₂)O₃₀
Cyclosilicate, osumilite group, forms a series with roedderite
Crystal System: Hexagonal
Specific gravity: 2.67 calculated
Hardness: 5 to 6
Streak: White
Colour: Colourless to faintly yellow or green
Common impurities: Ti,Al,Cr,Mn,Fe,Cu,Zn
Environments

Metamorphic environments

Localities

At the type locality, the Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany, eifelite occurs as platy to prismatic crystals in vesicles in contact metamorphosed basement gneiss xenoliths in leucite tephrite. Associated minerals include tridymite, sanidine, quartz, pyroxene group minerals, pseudobrookite, hematite and amphiboles (Mindat).

Eifelite from the Caspar Quarry - Image

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