Mineral Information and Data:

Fersmanite
Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3 [CNMNC approved formula]

Named for academician Aleksandr Evgen'evich Fersman (1883-1945), Russian mineralogist, geochemist, and gemologist.

IMA status : Valid species (Pre-IMA 1929) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
56.02.05.03  
  (56) Sorosilicate Si2O7 Groups and O, OH, F. and H2O
  (56.02) with cations in [4] and/or >[4] coordination
  (56.02.05) Mosandrite and related species
  
Nickel-Strunz
(10th edition) :
09.BE.72
  (09) Silicates
  (09.B) Sorosilicates (dimer) structures
  (09.BE) Si2O7 groups, with additional anions; cations in octahedral [6] and greater coordination
  
Crystal system: Triclinic System
Point group (H-M): 1 — pinacoidal
Space group: P1
Unit cell: a = 7.210(1)Å, b =7.213(2)Å, c = 20.451(3)Å, α = 95:15(3)°, β = 95:60(2)°, γ = 89:04(5)°, Z=8
Crystal Habit: Crystals commonly distorted, flattened, pseudotetragonal, to 2 cm.
Twinning: Possibly on {001}
  
Color: Dark brown to golden yellow
Diaphaneity: Transparent to translucent
Luster: Vitreous
Hardness (Mohs): 5 - 5.5
Measured Density: 3.44 - 3.46 g/cm3
Fracture: Uneven
Streak: White with pale brownish tint
  
Geologic Setting: In aegirine-rich nepheline pegmatites in a differentiated alkalic massif (Khibiny massif, Russia).
Mineral Association: Feldspar, pectolite, apatite, aegirine, lamprophyllite, rinkite, sulfides.
  

 

Fersmanite
Origin: Eveslogchorr Mtn., Khibina Massif,
Kola Peninsula, Russia (type locality)
Sample size: 6 x 4.5 x 2.5 cm
Photo: Rob Lavinsky

 

Fersmanite
(zoom-in of above)

<<< BACK TO MINERAL SEARCH