What is Eudialyte?
Eudialyte is a complex zirconium-bearing cyclosilicate, commonly red to pink and important in alkaline igneous rocks and rare-earth mineral collections.
Mineralogy and structure
Reference formula: Na15Ca6(Fe,Mn)3Zr3Si26O73(O,OH,H2O)3Cl2. Eudialyte has a large, compositionally flexible framework with channels and several partially occupied sites. Natural material is commonly intergrown, so the formula is a representative simplified composition.
Colour and appearance
Typical colours include red, pink, brown, black. The usual rhombohedral, granular, massive habit and vitreous, resinous lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Eudialyte forms in or is associated with alkaline nepheline syenites, agpaitic intrusions and late-stage cavities. Important documented localities include the Kola Peninsula, Russia, Greenland, Canada, Norway and Madagascar.
Collecting and care
Avoid strong acids and rough handling; some specimens contain radioactive or chemically complex accessory phases and should remain labelled.
Eudialyte in popular symbolism
Modern crystal guides sometimes associate Eudialyte with symbolic themes based on colour or collecting tradition. These associations are cultural interpretations, not mineralogical or medical properties.
