Page "Actinium" Paragraph 5

Actinium is a soft, silvery-white, radioactive, metallic element.

Its estimated shear modulus is similar to that of lead.

Owing to its strong radioactivity, actinium glows in the dark with a pale blue light, which originates from the surrounding air ionized by the emitted energetic particles.

Actinium has similar chemical properties as lanthanum and other lanthanides, and therefore these elements are difficult to separate when extracting from uranium ores.

Solvent extraction and ion chromatography are commonly used for the separation.