without lots of rummaging I seem to have somewhere a few extremely ornate carved miniature scenes using these nuts which probably date back to early-ish 20th c. Perhaps they were some of the curious souvenir items made for export from Hong Kong at the time?
(if you have my book "Beads!" some old and newer ones are shown on page 114, and in "the Bead Jewellery Book" on page 99).