Eveslogite

Eveslogite (Ca,K,Na,Sr,Ba)48[(Ti,Nb,Fe,Mn)12(OH)14Si48O144](F,OH,Cl)14] is a complex inosilicate mineral found on Mt. Eveslogchorr in Khibiny massif, Kola Peninsula, Russia. It is a monoclinic-prismatic mineral containing aluminum, barium, calcium, chlorine, fluorine, hydrogen, iron, manganese, niobium, oxygen, potassium, rubidium, silicon, sodium, strontium, tantalum, titanium, and zirconium. The name derives from the name of where it was encountered. This silicate mineral occurs as an anchimonomineral veinlet that cross-cuts poikilitic nepheline syenite.

Eveslogite derives its name from this locality, particularly from Mt. Evesglochorr. Since it is a newly discovered mineral, there has not been extensive research to show if it occurs in any significant amounts in other parts of the world.

General Information

  • Category: Inosilicate
  • Formula: (Ca,K,Na,Sr,Ba)48[(Ti,Nb,Fe,Mn)12(OH)14Si48O144](F,OH,Cl)14]
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m) (same H-M symbol)

Properties

The color of eveslogite is yellow or rather light brown. In addition, it is a semitransparent mineral that has a white streak and a vitreous luster. Its crystal system is monoclinic and possesses a hardness (Mohs) of 5. This newly discovered mineral belongs to the astrophyllite group of minerals and contains structures that are composed of titanosilicate layers.

  • Cleavage: perfect {001} and {010}
  • Fracture: splintery
  • Tenacity: brittle
  • Mohs scale hardness: 5
  • Luster: vitreous to resinous; silky
  • Streak: white and at times yellow-brown
  • Density: 2.85 g/cm3 (meas.) to 2.93 g/cm3 (calc.)

Occurrence

The particles of eveslogite are found in Mt. Eveslogchorr in the Khibiny Massif, Kola Peninsula, Russia. In particular, the geological occurrence of this mineral and the place of conservation for this mineral is Fersman Mineralogical Museum in Moscow Russia.

Eveslogite is commonly found in peralkaline granitoids, where it may be selectively included by certain major minerals (such as feldspar) or may form aggregates of multiple types of other minerals that are also found in the Russian mountain of Eveslogchorr.

 

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