Hopefully I'm understanding your question right XD.

It's not so much "magic" as it is more like an inate ability given to whom ever bears that stone. If you'd like to play a Guardian, I'm leaving it open for people to come up with their own ability.

Couple of examples to kind of clarify:

Danek the Strong- the ability granted by his stone maye be some manner of invulnerability.

Latsu the Clever- the ability may be some form of psychic ability or telekinesis.

The idea is that the ability relates back to the spirit who inhabits the stone.