The "essence" was, at its core, a type of energy. However, it was most useful when it was compressed into a solid state.
The solid version of the energy –and the origin of the glass analogy Gio was told– was the product that came from the raw energy: Genesis Crystals.
'Genesis Crystals have multiple uses, even putting aside Sequencers,' Gio thought as he approached the shining cables on the wall.
As an energy source, they were even better than Aether Shards in sustainability and efficiency. Their rarity made this use-case a waste of their potential, but it was possible to craft amazing armaments and equipment with them as a base.
For Sequencers, Genesis Crystals could be considered a type of enhancement.
'The great thing about them is that their energy is controllable.'