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Gadolinite-(Y)
Current inventory: 0 gems
 

Chemistry:  Y₂Fe²⁺Be₂(Si₂O₁₀)

Discovered in 1800;   IMA status: Valid (pre-IMA; Grandfathered).
Gadolinite is named after Finnish chemist, Johan Gadolin (1760-1852), who discovered Yttrium. The (Y) or (Ce) designations are added for either Yttrium or Cerium content.

Classification

Mineral Classification:

Silicates

Strunz 10th Ed. ID:

9.AJ.20

9 : Silicates
AJ : Nesosilicates with BO₃ triangles and/or B[4], Be[4] tetrahedra, cornersharing with SiO₄
20 : Datolite/Gadolinite group

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals rough; typically prismatic, terminated, and many other forms, to 25 cm; commonly massive.

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

Conchoidal or Splintery

Tenacity:

Brittle

Hardness (Mohs):

6.5 - 7.0

Density:

4.36 - 4.77 (g/cm³) (when non-metamict)

Luminescence:

None

Radioactivity:

(Y): Not Radioactive

(Ce): Weak; GRapi = 44,145.76 (Gamma Ray American Petroleum Institute Units)

Optical Properties

Color:

Black, greenish black, brown; grass-green to olive-green in thin fragments.

Transparency:

Transparent to Opaque

Luster:

Vitreous to Greasy

Refractive Index:

1.770 - 1.820  Biaxial ( + ), Isotropic when metamict

Birefringence:

0.0500

Dispersion:

Strong; r < v

Pleochroism:

None

Occurances

Geological Setting:

In granite and alkalic granite pegmatites.

Type Locality:

Ytterby, Resarö, Vaxholm, Stockholm, Sweden

Year Discovered:

1800

View mineral photos:

Gadolinite-(Y) Mineral Photos and Locations

More Information

Mindat.org  (Gadolinite-(Y)
Webmineral.com  (Gadolinite-(Y)

Gadolinite is a relatively rare mineral that is usually black and may be weakly radioactive if it contains Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Yttrium (Y).

Godolinite is available from several localities worldwide: Ytterby, Sweden; ResarÄo Island and elsewhere in Norway; Val Bedretto, Ticino, Switzerland; Badgastein, Salzburg, Austria; Loughborough Township, Frontenac County, Ontario, Canada. In the USA, in the Clear Creek pegmatite, Llano County, Texas; near Hackberry, Mohave County, Arizona; near Lake George, Park County, Colorado.
 

  
Gadolinite gems for sale:

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