Bloom

Bloom is created from cast iron, and is the precursor to wrought iron.

How to Acquire
Load bars of cast iron into a finery forge and fuel with two units of charcoal. Each bar will have a 50% chance of becoming bloom, and a 50% chance of becoming useless slag.

Update: Now when you use a Smithy's Hammer to turn bloom into either cast or wrought iron, there's a 40% chance for the quality of the iron to go down 20%, and there's also a 10% chance for the quality of the iron to go up 20%.