Törnebohmite-(La)
Törnebohmite-(La) is an IMA-recognized mineral species in the silicate class, with the chemical formula La₂Al(SiO₄)₂(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Fornacite structural group.
Key properties: Mohs hardness 5; specific gravity 4.805; Vitreous to greasy luster; optically biaxial.
IMA symbol Tbh-La, IMA status: approved, named in 1962.
Replaces cerite, in turn replacing bastnÄa site, in granite pegmatite in the fenitization zone of a nepheline syenite massif.
It is found associated with Cerite, bastnÄasite, allanite, feldspar.
The name refers to its content of lanthanum and relation to tÄo rnebohmite-(Ce).
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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