Gadolinite

Gadolinite

By Tim Matthews, JD, FGA, GG, DGA,
CEO and President of JTV (retired)
Published: June 2014
Modified: September 2023
Gadolinite Polished

Ranging from green to brownish black in color, gadolinite is a mineral that counts Russia as one of its primary sources. Interestingly, gadolinite is prized for the two rare earth elements it contains: yttrium and cerium.

General Information

Common Name
Gadolinite
Species
Gadolinite
Transparency
Transparent - Opaque
Dispersion
Strength: Strong Fire
Refractive Index
Over The Limit 1.770-1.820
Birefringence
0.010- 0.050
Optic Character
Biaxial
Optic Sign
Positive
Polariscope Reaction
Doubly Refractive (DR)
Pleochroism
None
Hardness
6.5-7
Streak
White And Greenish Gray
Specific Gravity
4.000-4.650
Toughness
Poor
Luster
Vitreous, Resinous, Greasy
Fracture
Conchoidal, Splintery
Cleavage
None
Chemical Formula
Y2Fe2+Be2(Si2O10) or (Ce,La, Nd,Y)2Fe2+Be2(Si2O10)
Crystal System
Monoclinic
Chemistry Classification
Silicate

Gadolinite Colors

  • Black Gadolinite
    Black
  • Brown Gadolinite
    Brown
  • Green Gadolinite
    Green

Alternate Names

Ytterbite

Countries of Origin

Russian Federation; Angola; Czechia; United States of America; Madagascar; Kazakhstan; United Kingdom of Great Britain and Northern Ireland; Portugal; Austria; Mongolia; Sweden; Mozambique; Pakistan; Korea (the Republic of); Unknown; Malawi; China; Brazil; Poland; France; Argentina; Hungary; Sri Lanka; Japan; Switzerland; India; Spain; Canada; Norway; Namibia; Finland; Denmark; Italy; South Africa; Australia; Germany; Tajikistan

Care

Care must be taken with Gadolinite because the material is soluble in acid and is radioactive.