Outstanding white tabular crystals of the rare REE mineral lanthanite-(La) from the famous Bastnas deposit in Sweden (Bastnäs Mines, Riddarhyttan, Skinnskatteberg, Västmanland County, Sweden). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Lanthanite-(La)
Lanthanites are a group of isostructural rare earth element (REE) carbonate minerals. This group comprises the minerals lanthanite-(La), lanthanite-(Ce), and lanthanite-(Nd). This mineral group has the general chemical formula of (REE)2(CO3)3·8(H2O). Lanthanites include La, Ce, and Nd as major elements and often contain subordinate amounts of other REEs including praseodymium (Pr), samarium (Sm), europium (Eu) and dysprosium (Dy).
Intro adapted from Wikipedia (CC BY-SA).
Lanthanite-(La) is an IMA-recognized mineral species in the carbonate class, with the chemical formula La₂(CO₃)₃·8H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbnb). It is a member of the Lanthanite structural group.
Key properties: Mohs hardness 2.5; [White.] streak; [Vitreous to pearly.] luster.
IMA symbol Ltn-La, IMA status: approved, named in 1845.
A rare secondary mineral typically formed by alteration or weathering from earlier rare-earth-element-bearing minerals.
It is found associated with Allanite-(Ce) (Saucon Township, Pennsylvania, USA).
The name refers to dominant lanthanum in its composition.