Onyx is a variety of chalcedony that grows in parallel layers. The gemstone occurs in a handful of colors, when it's red it's often referred to as sardonyx. The layers of onyx can be used to striking effect when carved into cameos or intaglios, or they can be employed subtly when cut nicolo (a translucent layer of white atop the colored of base with a beveled edge) as in the case of this Victorian locket. The shield-shaped locket is made in heavy 18k yellow gold and holds two locket compartments within. Hangs from a new 16" 14k gold chain.