Diamond In The Rough

When a dragon's fireball lands near obsidian, it will turn into an obsidian diamond ore. This block is a combination of the properties of obsidian and diamond ore.

The chance for obsidian turning into diamond ore is configurable via gamerule.

As of version 1.1.0, you can change the blocks that generate with the fireballs by changing the "dragon_made_ores" block tag.