Lignum nephriticum cup manufactured from narra Wooden (the namesake of your province) manufactured opalescent colors when water is poured into it. These picket cups have been a major pre-colonial and colonial marketplace of Naga. Naga would be the native pre-colonial name of the city. It is actually named following https://andremykwg.thezenweb.com/a-secret-weapon-for-23naga-66008753