http://lodestone.finalfantasyxiv.com...f271d7a0a84d5f

Q. What happens exactly when the harnessed element of a synthesis attempt becomes unstable?
A. When an element of a synthesis becomes unstable, the following effects take place respectively:
Lightning: Progress greatly reduced
Wind: Durability consumption greatly increased
Fire: Quality greatly reduced
Ice: Progress reduced, chance of aetherial sparks reduced
Earth: Durability consumption increased, chance of aetherial sparks increased
Water: Quality reduced, chance of aetherial sparks increased