Nacre: The shiny, iridescent substance secreted by a mollusk as a response to an irritant, like a piece of sand. Over time layers of nacre build up to become a pearl.
Naja (or "Najah") (pronounced Na-Ha): From the Navajo word "Najahe", meaning "crescent": A crescent-shaped silver ornament believed to go back to Moorish designs that was originally a forehead pendant on horse bridles. It is now commonly found pendant from the bottom of a squash blossom necklace. (see also "Squash Blossom")
Navette cut: Alternate name given to the marquis cut. See "marquis cut".
Niello: A black metallic alloy of sulfur, copper, silver, or lead, used as inlay for an incised design on the surface of another metal. Niello refers to both the substance and the process