Throwable Meteor Chunk
Throwable Meteor Chunks are crafted by putting Raw Meteoric Iron in a crafting table. Doing this will give you three of them. You can throw them right-clicking and then pick them up from the ground when they fall. You can also smelt them in a furnace to get a Hot Throwable Meteor Chunk that deals more damage and sets players and mobs alike on fire, although it is only hot for 45 seconds.
If you keep a Hot Throwable Meteor Chunk in a storage slot (chest, cargo rocket, furnace), it will never cool down. This is due to the fact that it only cools down when it's in someone's inventory.