Gem Perfection

Gem Perfection is a passive trait exclusive to Jewelcrafters. It gives a chance when cutting Northrend and Cataclysm gems to cut it into a "perfect" gem, slightly raising its stats (by 15% or more).

Quest source
Once you reached Level 50, you were eligible for the starting quest offered by any of the Northrend starting area trainers (These quests seem not to require a certain Jewelcrafting skill):