Mineral Information and Data:

Gadolinite-(Ce)
Be2Fe2+Ce2Si2O10 [CNMNC approved formula]

Named as the Ce-predominant rare earth element in the gadolinite group. Group named for the Finnish chemist, Johan Gadolin (1760-1852), who discovered yttrium. Named per nomemclature of rare-earth minerals (IMA, 1966).

IMA status : Approved Species 1978 ()
CLASSIFICATION 
Dana
(8th edition) :
54.02.01b.02  
  (54) Nesosilicate Borosilicates and Some Beryllosilicates
  (54.02) with B in [4] coordination
  (54.02.01b) Datolite group (Homilite series)
  
Nickel-Strunz
(10th edition) :
09.AJ.20
  (09) Silicates
  (09.A) Nesosilicates (Isolated tetrahedron) structures
  (09.AJ) Nesosilicates with BO3 triangles and/or B[4], Be[4] tetrahedra, cornersharing with SiO4
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Space group: P2/c
Unit cell: a =4.82(2)Å, b = b = 7.58(2)Å, c = 10.01(3)Å, β = 90.466°, Z=2
Crystal Habit: Metamict; monoclinic after recrystallization at 700°C. As irregular highly-fractured masses, to 2 cm.
  
Color: Black; in thin section, olive-green
Diaphaneity: Translucent
Luster: Vitreous
Hardness (Mohs): 6.5 - 7
Measured Density: 4.20 g/cm3
Fracture: Conchoidal
  
Geologic Setting: In syenite pegmatite veins along a contact between basalt and monzonite.
Mineral Association: Aegirine, pyrochlore, zircon, apatite, titanite, pyrophanite, magnetite, loparite, chevkinite, biotite, microcline, helvite, molybdenite, albite, apophyllite, quartz, calcite
  
Other Properties: Gemstone Extremely Rare.

 

Gadolinite-(Ce)
Brown rough surface, prismatic gadolinite-(Ce) crystal.
Mineral identification confirmed by X-ray diffraction and chemical analysis.
Photo: © RRUFF Project

<<< BACK TO MINERAL SEARCH