 They were indicative of a very active ancient maritime trading region that imported and exported raw jade and finished jade ornaments known as the Sa Huynh-Kalanay Interaction Sphere.They were produced during a period between 500 BCE to as late as 1000 CE, although later examples were replaced with metal, wood, bone, clay, green mica, black nephrite, or shell materials, rather than green jade.Polished and ground stone adzes, gouges, and other implements, some of which are made from jade-like stone, have also been recorded in areas of Island Melanesia and eastern New Guinea associated with the Lapita culture.