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+
)
20O
38 discovered at Radium Hill mine, South Australia in 1906 and named by Douglas Mawson for Australian geologist Tannatt William Edgeworth David (1858-1934).[7] - Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe3+
)
20O
38 first described in 1960 from Vemork, Iveland, Norway.
| Davidite-(La) | |
|---|---|
 Davidite-(La) from Kazakhstan | |
| General | |
| Category | Oxide minerals |
| Formula (repeating unit) | (La,Ce,Ca)(Y,U)(Ti,Fe3+ ) 20O 38 |
| IMA symbol | Dvd-La[1] |
| Strunz classification | 4.CC.40 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) H-M symbol: (3) |
| Space group | R3 |
| Unit cell | a = 10.376, c = 20.91 [Å]; Z = 3 |
| Identification | |
| Color | Black |
| Fracture | Subconchoidal to uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 6 [2] |
| Luster | Vitreous |
| Diaphaneity | Opaque, translucent in very thin fragments |
| Specific gravity | 4.33 to 4.48 |
| Alters to | Metamict |
| Other characteristics |  Radioactive |
| References | [3][4][5][6] |
References
edit- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ "Davidite-(La) Mineral Data".
- ^ Davidite-La in Handbook of Mineralogy
- ^ Davidite-La on Mindat
- ^ Davidite-(La) on Webmineral
- ^ Davidite-(Ce) on Webmineral
- ^ Branagan, D.F. (2005): T.W. Edgeworth David: A Life: Geologist, Adventurer and "Knight in the Old Brown Hat", National Library of Australia, Canberra, p. 471. ISBN 0 642 10791 2