Porcelain or Ceramic (?) Hibiscus Pattern Napkin Rings Set of Eight

Nice formal vintage napkin rings by Andre Richard - not sure if they are ceramic or porcelain but they are white glazed rings with a flattened side to prevent rolling, featuring a mint green stripe and pink hibiscus bloom pattern. Could go great with Asian or beach decor. Old but never put to use. Most rings still are labeled by the shop they were purchased from. Set of eight.