Alluring Onyx and Swarovski Crystal Yellow Gold Ring Genuine Natural High Quality- Semi-Precious Stones - Hand-Prong Set -Hand Finished - Nickel Allergy Free, Base Metal- Brass, 18KTGP Yellow Gold Electroplate Finish With Swarovski Crystals. Black onyx crystals can be used for grounding, protection, and self-control, and as a shield against negative energy. It also enhances discipline, allowing more ease in following through on goals and completing tasks. Size 7 View photos for further details