My condolences on your loss. I think making these pearls into something influenced by your mom but infused with "you" is one of the best tributes you can pay to her.
I've been searching online for you to try to come up with pieces that were Stevie-ish... I'm not sure how feasible a necklace with additional gems would be for you, but here are a few examples:
Pearl and Sapphire (I really love this one):
Mercy pearl, but it the pendant seemed Nicks to me:
Earrings:
