a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.

Metallic praseodymium like this is not much used, but when mixed into glass it provides a precise blue color that filters out the yellow glow of molten glass, allowing glassblowers to see their work clearly.