Scrimshaw is ivory which has been adorned with carved or coloured designs. It’s intimately associated with American whalers, who used walrus tusks and bits of whale teeth and jawbone to carve intricate designs in the few spare moments they had free.
The tools used are of the roughest. Some old files, softened in the fire, and filed into grooves something like saw-teeth, are most used; but old knives, sail-needles, and chisels are pressed into service. The work turned out would, in many cases, take a very high place in an exhibition of turnery, though never a lathe was near it.
The Cruise of the Cachalot, by Frank T Bullen, 1899.
The best work of these times is still highly prized and very collectable. Someone who practises the craft is a scrimshoner.
The origin of the word is mysterious; it was first recorded about 1825, but its spelling in the first half of the nineteenth century was highly variable, with forms such as scrimshonting, scrimshonging, scrimshandy, scrimshanking and skrimshander all appearing at various times. There’s some suggestion that our modern spelling was influenced by the proper name Scrimshaw, but nobody seems to know quite why. Since a person who did this on board ship wasn’t working, it may be that the British English scrimshank, to shirk one’s duty, came from the same source.