Scoria Ore is a Hardmodeore which generates in the Abyssbiome. It can be found on the underside of the floating Abyss Gravel islands, dropping harmful lava particles into the water beneath itself. These lava particles have a base damage of 25.
Scoria Ore cannot be destroyed by explosives, even after Golem has been defeated.
Unlike most other ores, this ore does not require a boss to be defeated in order to be mined aside from the Picksaw requirement, meaning that it can be mined even in a Pre-Hardmode world.
The lava particles that this ore drops can provide natural light to the normally pitch-black Abyss.
Trivia
Scoria is a type of igneous rock with similar properties to basalt.
Scoria Ore used to be known as Chaotic Ore, and is still referred to as such in the mod's files.
This ore used to generate in The Underworld, but it was later relocated to the Abyss.
This was to give further incentive to explore the Abyss, and also because the ore had issues with generating into the Underworld's ruined houses.