Gagarinite-(Ce)
| Gagarinite-(Ce) | |
|---|---|
| General | |
| Category | Halide mineral |
| Formula (repeating unit) | Na(REExCa1−x)(REEyCa1−y)F6 |
| IMA symbol | Gag-Ce[1] |
| Strunz classification | 03.AB.35 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) H-M symbol: (3) |
| Space group | P3 |
| Unit cell | a = 6.099 Å, c = 11.064 Å, Z = 3 |
| Identification | |
| Color | Colorless, pale pink, orange |
| Crystal habit | Granular |
| Cleavage | None |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 3.5 |
| Luster | Vitreous |
| Diaphaneity | Transparent |
| Specific gravity | 4.44–4.55 |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 1.483, nε = 1.503 |
| Birefringence | δ = 0.020 |
| References | [2][3] |
Gagarinite-(Ce) previously zajacite-(Ce) is a rare radioactive fluoride mineral with formula Na(REExCa1−x)(REEyCa1−y)F6. REE refers to rare-earth elements, mostly those belonging to the lanthanide series. It crystallizes in the trigonal rhombohedral system and has a white vitreous appearance with a conchoidal fracture. It has a Mohs hardness of 3.5 and a specific gravity of 4.44 to 4.55. Zajacite is transparent with refractive indices nω = 1.483 and nε = 1.503.[3] Gagarinite-(Y) is a yttrium-rich analog.
It occurs as creamy to white anhedral to subhedral grains in pegmatite and aplite pods or lenses in a peralkaline igneous intrusion.
It was discovered in 1993 at , Quebec – Labrador, (56°20'N, 64°10'W) and was initially named for , who led the expedition responsible for its discovery, and who first recognized the presence of the new mineral. The mineral was renamed gagarinite-(Ce) in 2010 by the IMA.[2][4] The new name is for Russian cosmonaut Yuri Gagarin (1934–1968).[2]
See also[]
References[]
- ^ 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.
- ^ a b c Gagarinite-(Ce) on Mindat.
- ^ a b Webmineral data.
- ^ Mineralienatlas in German.
- Lanthanide minerals
- Sodium minerals
- Calcium minerals
- Fluorine minerals
- Trigonal minerals
- Minerals in space group 147
- Halide mineral stubs