Reminiscent of a starry night, the intricately-cut sparking white topaz make this ring a sure eye-catcher. Expect side glances and compliments every time you wear it! 18K gold bimetal on blackened sterling silver. Size approx. 7.5. Gold bimetallic an affordable alternative to solid gold that is manufactured by rolling and bonding under heat and pressure a thin layer of 18K gold on a substrate of sterling silver.