Aaron's soul stone
Soul Stones are smooth pieces of glowing rock that represent the essence of who a person is. To acquire a soul stone, one must travel to The North Star where all the soul stones are kept. If two people are soul mates, their soul stones will fit together perfectly, however if they are not soul mates, the stones will not fit and there is no way to make them if it isn't destined.
Sabrina and Harvey's stones fit perfectly together.