Ruined Portal

Ruined portals are naturally generated damaged nether portals, which spawn in both the Nether and the Overworld.

Generation
Ruined portals generate in all biomes in both the Nether and the Overworld. They can spawn underground, underwater, or exposed to the air. Natural terrain around ruined portals will generate as netherrack.

Structure
Ruined portals generate incomplete portal frames composed of both obsidian and crying obsidian, despite the latter not being a valid portal material. Some frames generate flat on the ground, as if they toppled over.

Ruined portals generate with a chest, which contain various materials related to nether portals as various golden items.

If a ruined portal generates in the Overworld it will be surrounded with structures made of stone, stone bricks and iron bars; if in the Nether it will be surrounded by blackstone variants and chain.

If a ruined portal generates underwater, it may create downward bubble columns with nearby magma blocks.

Currently there are 13 variants. 10 normal size portals and 3 giant portals in varying states of decay.

Ruined portals can be generated by the player by loading  or   with a structure block