In the bags of unsold jewelry that I've bought recently there have been quite a few necklaces with broken pendants (I'm referring to necklaces where the pendant is part of the necklace itself rather than hanging from it). I've removed the pendants and added new ones taken from other items of jewellery that needed to be refurbished. These are the most recent examples:
Crafty Green Poet Etsy shop here.
I've also incorporated tiger eye into a few pendants like this, I blogged about those here. I also have a few left over tiger eye stones to incorporate into future necklaces (or other items).