Lepersonnite-(Gd) is a very rare-earth element and uranium mineral with the chemical formula Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24·48H2O. It occurs with bijvoetite-(Y) in the Shinkolobwe deposit in the Democratic Republic of the Congo, famous for rare uranium minerals. It is the only confirmed mineral with essential gadolinium[2][4][5] and is named after the Belgian geologist Jacques Lepersonne.
| Lepersonnite-(Gd) | |
|---|---|
-Studtite-Curite-201138.jpg) Lepersonnite-(Gd) (flat crystals) intergrown in the yellow studtite clusters (needles) and orange curite. | |
| General | |
| Category | Carbonate mineral |
| Formula (repeating unit) | Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24·48H2O |
| IMA symbol | Lps-Gd[1] |
| Strunz classification | 5.EG.10 (10 ed) 8/B.38-10 (8 ed) |
| Dana classification | 17.1.12.1 |
| Crystal system | Orthorhombic |
| Crystal class | Pyramidal (mm2) and dipyramidal (mmm) |
| Space group | Pnnm or Pnn2 |
| Identification | |
| Color | Yellow (bright) |
| Crystal habit | Needle-like crystals in crusts (mammilary) or spherules |
| Specific gravity | Fass |
| Density | 3.97 (measured) |
| Optical properties | Biaxal (-) |
| Refractive index | nα = 1.638, nβ = 1.666, nγ = 1.682 |
| 2V angle | 73° (calculated) |
| Other characteristics |  Radioactive |
| References | [2][3][4] |