Just looked at my achievements for ib2 and I have one at the bottom that I believe is new?
"Forge a rainbow gem."
Soooooo what's a rainbow gem?
The official formula for the Rainbow Gem is as follows (Gems must be in this order!):
Fire defense + ice defense + water defense = light defense
Shock defense + poison defense + wind defense = dark defense
Light defense (forged) + dark defense (forged) + hexagonal gem = Rainbow (all defense) Gem