Hook: Centerpiece (Giant Purple Square)The Ancestral Graveyard decoration fits into a giant purple square floor hook with beams of light.
How to Get an Ancestral Graveyard Decoration
Cartel Pack Decorations
The Ancestral Graveyard decoration can be dropped from Ultimate Cartel Packs, which were released on the Cartel Market and bought with Cartel Coins. Cartel Packs, including the Ultimate Cartel Pack, include a random selection of items from the Ultimate Cartel collection of items. You aren't guaranteed to get an Ancestral Graveyard decoration from a Ultimate Cartel Pack, but it is one of the few ways to get an Ancestral Graveyard deco apart from buying it on the GTN from another player.
If you're looking to get a Ancestral Graveyard, the easiest way to get it is to head to the Galactic Trade Network (GTN) in SWTOR and buy it with credits from another player. If it's very rare and not available on the Cartel Market, you could try buying from the GTN and hope you get it.