Forum:Vlyon prism effect still work when detach form xyz monster

Vylon prism - If this card is sent from the Monster Card Zone to the Graveyard: You can pay 500 Life Points to target 1 face-up monster you control; equip this card to that target. If the equipped monster attacks or is attacked: It gains 1000 ATK during the Damage Step.

I know xyz material are not consider on the field but do they still occupied a monster zone with the xyz monster.

On the forum of summoning a xyz monster (http://yugioh.wikia.com/wiki/Xyz_Summon)

4th paragraph - Xyz Materials are not sent to the Graveyard. Instead, they are placed on the same Monster Card Zone beneath the Summoned Xyz Monster.

if Vlyon Prism occupied a monster card zone and it sent to the graveyard, then for sure it effect works.

also on the forum of xzy material (http://yugioh.wikia.com/wiki/Xyz_Material)

1st paragraph, 2nd sentence - When an Xyz Monster is Summoned, the monsters used in the Xyz Summon are stacked underneath the monster instead of being sent to the Graveyard (called "overlaid" in the anime), and so only one Monster Card Zone is occupied.