Lignum nephriticum cup made from narra wood (the namesake of the province) manufactured opalescent colors when h2o is poured into it. These wooden cups had been A serious pre-colonial and colonial industry of Naga. Naga would be the indigenous pre-colonial title of town. It's named following the narra tree https://brooksguhse.bloggactivo.com/27825639/23naga-for-dummies