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 Primarium Z was first seen in SM106 under the ownership of Ida, who had received it from Kanoa. She used it to have her Primarina perform Oceanic Operetta. Later on, Ida gave another Primarium Z to Lana.