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 Evolving Research!, under the ownership of Ida. She used it to have her Primarina perform Oceanic Operetta. Later on, Ida gave Lana a different Primarium Z, which Kanoa had found while diving in the sea.