Java Man wrote:
Combinations of assorted 'power crystals" you crush on your hand and absorb the essence from.
"Absorb". Aka "totally not going scarface into those powders of might here" :')
You could always reflavor them like spell-ish things that take a different route. Like some old, all-but-forgotten rune magic that puts some essence into a more subtle package than the vocal, somatic evocation (hah) of spells.
As with a lot of classes, one can ask "What's in a name?"