Definition of "ambergreece"

We found great ſtore of Ambergreece, which the Indians call Pirapoun Arepoty, here fortune was ſomewhat fauourable vnto me, for I got aboue fiue hundred Crownes in this iourney.

1591, Antonie Knivet, “The admirable aduentures and ſtrange fortunes of Maſter Antonie Knivet” (chapter VII), in Samuel Purchas, compiler, Pvrchas his Pilgrimes, volume 4, London: H. Fetherston, published 1625, page 1224

[…] we were cloſe by the Peninſule Mozambique (part of Quiloa) inhabited by Negroes; abundant in Gold, Silver, and Ambergreece […]

1638, Sir Thomas Herbert, Some yeares travels into divers parts of Asia and Afrique