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Mosandrite
Current inventory:  1 gem
 

Chemistry:  (Na,Ca)₃(Ca,Ce)₄(Ti,Nb,Al,Zr)(Si₂O₇)₂(O,F)₄

Discovered in 1841;   IMA status: Valid (pre-IMA; Grandfathered).
Mosandrite is named for Carl Gustav Mosander (1797-1858), Swedish chemist and mineralogist, who discovered several Rare Earth Elements.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/C.12-25

8 : Silicates
C : Sorosilicates, with [Si2O7]6-, without anions unfamiliar to tetraheders
12 : Götzenite - Nacareniobsite-(Ce) series

Crystal Data

Crystallography:

Monoclinic - Sphenoidal

Crystal Habit:

Crystals are Prismatic - Crystals Shaped like Slender Prisms

Twinning:

None

Physical Properties

Cleavage:

[100] Good

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

4.0

Density:

3.29 (g/cm³)

Luminescence:

None

Radioactivity:

Weak; GRapi = 23,082.68 (Gamma Ray American Petroleum Institute Units)

Optical Properties

Color:

Yellow, Yellowish green, Reddish brown, Brown

Transparency:

Transparent to Translucent

Luster:

Vitreous (glassy)

Refractive Index:

1.646 - 1.658  Biaxial ( + )

Birefringence:

0.0120

Dispersion:

Strong; r > v

Pleochroism:

None

Occurances

Geological Setting:

n/a

Type Locality:

Låven (Skådön), Langesundsfjorden, Larvik, Vestfold, Norway

Year Discovered:

1841

View mineral photos:

Mosandrite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Mosandrite is an extremely rare gem that is a complex sorosilicate and is weakly radioactive due to its Cerium content. Mosandrite crystals are usually heavily included and very rarely found as gem quality. The main source of facetable crystals is Kukisvumchorr Mountain, Kola Peninsula, Murmansk District, Russia.
 

  
Mosandrite gems for sale: