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.
This is artwork of the Lunalium Z as seen on the official Pokémon Global Link.
Lunalium Z
In the anime
In SM090, Gladion received a Lunalium Z from Lunala. Together with Ash and Nebby, Gladion and Lunala performed the Z-Move and provided enough light to help Necrozma restore its Ultra form.