Includes 20 inch necklace cord. To request an 18inch or 24inch cord, please leave a note for seller at checkout. Oxidized Copper Green Opal is a stone that's all about the heart. This crystal is here to provide nourishing and rejuvenating energies to anyone struggling with emotional heartache. Its a perfect stone for anyone who may have gone through recent trauma or grief, the dissolution of a relationship, or a hurtful disagreement.