Natural occurrence: Decay product

Elements exist independently of human intervention only through the radioactive decay of others. They do not have a stable nuclide.

Technetiumshiny gray metal

Astatineunknown, probably metallic

Radoncolorless gas

Radiumsilvery white metallic

Actiniumsilvery-white, glowing with an eerie blue light; sometimes with a golden cast

Protactiniumbright, silvery metallic luster

Neptuniumsilvery metallic

Plutoniumsilvery white, tarnishing to dark gray in air

Legend