The Stone Ruins is part of the City Builder System. The Stone Ruins is made of "Dwarvenite". The Stone Ruins was initially available as Add-On item during the City Builder System Kickstarter. The item comes in both painted and unpainted versions.
The Stone Ruins comes with these 19 pieces:
(6) Corner, Stone, Ruined
(3) Floor, Stone, Ruined
(4) Rubble, Stone
(6) Wall, Stone, Ruined (3 part)