White amorphous powder. Density 7.407g/cm3. Melting point 2330 + 20 C. Insoluble in water, soluble in acid to form the corresponding salt. It is easy to absorb water and carbon dioxide in the air, and can work with ammonia to produce gadolinium hydrate precipitate. It is used as the additive of gadolinium iron garnet, yttrium aluminum garnet, medical equipment industry as the sensitizing fluorescence material, and can also be used as the additive of the optical prism.