Silvery, white metal that becomes yellowish in contant with air .
In nature, praseodymium is found in the Earth's crust, 5.5-9.1 ppm, in rare earth minerals . The isotope found in nature is 141Pr (100 %, stable) .
In pure solid form, praseodymium exist in the following forms:
α-form: hexagonal crystal at < 798 °C 
β-form: body-centered cubic crystal at > 798 °C