Eifelite - Encyclopedia
Class : Silicates
Subclass : Cyclosilicates
Crystal system : Trigonal
Chemistry : KNa3Mg4Si12O30
Rarity : Very rare
Eifelite is an extremely rare silicate from the milarite group which constitutes a series with roedderite. It is found in blocks of gneissic xenoliths ejected by leucite tephrites from a volcano. Its name comes from its place of discovery : the Bellerberg volcano near Ettringen in the Eifel Massif (Germany). It is only known in small crystals of 1 mm maximum, colorless or faintly tinted with green or yellow.
Main photo : Eifelite from Caspar quarry, Ettringen, Mayen-Koblenz, Germany © Stephan Wolfsried
Eifelite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fake listed for this mineral species.
Hardness : 5 to 6
Density : 2.67
Fracture : Undeterminated
Streak : White
TP : Transparent
RI : 1.543 to 1.546
Birefringence : 0.001
Optical character : Uniaxial +
Pleochroism : None
Fluorescence : None
Solubility : Insoluble
Magnetism : None
Radioactivity : None