| Elementi | Grado | ||||||
| Pr6O11/REO % min | 99.999 | 99.99 | 99.95 | 99.9 | 99.5 | 99 | |
| Impurità terre rare % max | La2O3 | 0.0005 | 0.001 | 0.002 | 0.003 | 0.01 | totale |
| CeO2 | 0.0005 | 0.002 | 0.01 | 0.03 | 0.05 | 1 | |
| Nd2O3 | 0.001 | 0.004 | 0.03 | 0.05 | 0.4 | - | |
| Sm2O3 | 0.0001 | 0.001 | 0.005 | 0.01 | 0.02 | - | |
| Y2O3 | 0.0005 | 0.001 | 0.002 | 0.005 | 0.01 | - | |
| Altro REO | totale | totale | totale | totale | totale | - | |
| 0.0001 | 0.001 | 0.001 | 0.002 | 0.01 | - | ||
| Impurità non rare % max | Fe2O3 | 0.0005 | 0.0005 | 0.002 | 0.005 | 0.01 | 0.01 |
| SiO2 | 0.005 | 0.005 | 0.01 | 0.01 | 0.01 | 0.01 | |
| CaO | 0.001 | 0.005 | 0.01 | 0.03 | 0.04 | 0.05 | |
| Na2O | 0.01 | 0.01 | 0.02 | 0.03 | 0.04 | 0.04 | |
| A1203 | 0.01 | 0.01 | 0.01 | 0.01 | 0.05 | 0.05 | |
| Cl- | 0.001 | 0.005 | 0.015 | 0.03 | 0.03 | 0.05 | |
| SO42 | 0.02 | 0.02 | 0.02 | 0.03 | 0.04 | 0.05 | |
| altri | 0.005 | 0.01 | 0.01 | 0.01 | 0.02 | 0.03 | |
| contenuto di acqua % max. | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | |
| L.O.I % max | 0.98 | 0.98 | 0.98 | 0.98 | 0.98 | 0.98 | |