Obsidian Ore

Block
Obsidian ore spawns between the Y levels of 1 and 13. When broken, it drops 2 Obsidian Shards.

Mod
Obsidian Ore was a minecraft mod built in MCreator on minecraft version 1.12.2 which added an ore that dropped obsidian shards, which would be turned into obsidian blocks. It was discontinued when its features were all implemented into Subterranean Switcheroo.

You can see all the content that was once in Obsidian Ore here.