Diagram: Hardened leather is a crafting diagram in The Witcher 2: Assassins of Kings that is needed to craft hardened leather.
It can be purchased from one of the following merchants:
- Fioravanti in Flotsam
- Mysterious merchant in Flotsam's harbour
- Sambor in the camp followers' encampment
- Felicia Cori in Vergen's Rhundurin Square (Chapter II, Iorveth's path) and in Loc Muinne (Chapter III)
- The Incredible Lockhart in Loc Muinne