Forsaken Temple - Walls and Pillars is part of the Dungeon of Doom series. It is made of "Dwarvenite." This item was initially available as an add-on pack during the Dungeon of Doom Kickstarter. The item comes in two painted versions (standard stone and red marble and the limited edition with jade and gold accent) and an unpainted version.
Forsaken Temple - Walls and Pillars comes with these 12 pieces:
(8) Freestanding Forsaken Wall
(4) Serpentine Corner Pillar