Lignum nephriticum cup product of narra wood (the namesake from the province) created opalescent colors when h2o is poured into it. These wood cups were An important pre-colonial and colonial sector of Naga. Naga may be the native pre-colonial title of the city. It's named once the narra tree https://daltonhuesd.pages10.com/considerations-to-know-about-23naga-64885423