The Icium Z (Japanese: コオリZIce Z) is a type of Z-Crystal introduced in Pokémon Sun and Moon. It is the type-specific Z-Crystal associated with the Ice type and allows Pokémon to upgrade their Ice-type moves to Z-Moves.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot remove a Z-Crystal from a Pokémon.
A full set of type-specific Z-Crystals, including the Icium Z, appeared in SM109, where Hapu allowed Ash to choose his grand trial prize from amongst them.