Gem usage

[Agema]

A gem used to raise a level to make it possible to cast the spell does NOT count towards the inherent gem cost of the spell.

An E2 mage can use 2 gems. Therefore it can cast an E3 spell that costs 1 gem to cast, using one to raise level, and the other to match the inherent spell cost.

The E2 mage cannot cast an E3 spell that requires 2 (or more) gems, because as the mage can only use 2 gems, it would spend one to raise path level, and then cannot meet the casting cost.