Davidite-(La) Locality: Beqtau-Ata (Bektau-Ata), Qaraghandy Oblysy (Karaganda Oblast'), Kazakhstan ( Locality at mindat.org ) This rare earth crystal is characterized by brilliant metallic luster along with a silver-black color. Although slightly rough around the perifera, it is nevertheless complete and VERY large for the species. Slightly radioactive. A rare mineral indeed! 3.6 x 3.5 x 1 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Davidite-(La)
Davidite is a rare earth oxide mineral with chemical end members Lanthanum (La) and Cerium (Ce). It exists in two forms: Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe3+)20O38 discovered at Radium Hill mine, South Australia in 1906 and named by Douglas Mawson for Australian geologist Tannatt William Edgeworth David (1858-1934). Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe3+)20O38 first described in 1960 from Vemork, Iveland Municipality, Norway.
Intro adapted from Wikipedia (CC BY-SA).
Davidite-(La) is an IMA-recognized mineral species in the halide class, with the chemical formula La(Y,U)Fe₂(Ti,Fe,Cr,V)₁₈(O,OH,F)₃₈.
It crystallizes in the trigonal crystal system (space group R-3). It is a member of the Crichtonite structural group.
Key properties: Mohs hardness 6; specific gravity 4.33–4.48; Grayish black to dark brown streak; Vitreous to submetallic, shining luster; optically isotropic.
IMA symbol Dvd-La, IMA status: approved, named in 1906.
Found as a primary mineral in high-temperature hydrothermal veins; in norite and anorthosite; in alkalic rocks and also granite pegmatites and carbonatites.
It is found associated with Rutile, titanite, magnetite, ilmenite, apatite, tourmaline, epidote, albite, calcite.
The name refers to Professor Tannatt William Edgeworth David (1858–1934), Australian geologist, University of Sydney, Sydney, Australia. All rights reserved.