Quattro Teschi d'oro - Black Sapphire Gold-Tone Wedding/Engagement Ring (#w042)'Quattro Teschi d'Oro' Black Sapphire Gold Tone Wedding Engagement Ring Metal : Rhodium w Gold overlay Stone : Black Sapphire* (round cut ) *What Is Black Sapphire? Black sapphire is a nearly opaque stone whose color is so dark that it appears to absorb all light that enters the gemstone. Because of its color, black sapphire is often confused with onyx. Indeed, this stone can successfully act as an onyx substitute. Although both stones look very