The brutality of penal colonies in Oceania has been well told by convict Henri Charriere and famously played out on screen by Steve McQueen in Franklin J. Schaffner’s ‘Papillon’. What remain less known are the winsome stories of art and craft produced by convicts and traded beyond the prison walls. In the penal colonies of New Caledonia nautilus, burgos and oyster shells, harvested off the coast and from near-by Vanuatu, became canvasses for convicts to carve images of local life, to copy printed plates by the masters, or to celebrate scenes of the empire that had condemned them. For the visiting Parisian the ‘shell portrait’ was a coveted variation on the common calling card and the mother-of-pearl pin, pendant or earring an exotic twist on metropolitan fashion. This article explores the rise of convict art and craft produced in the New Caledonian prison workshops from its clandestine beginnings as illegal trade to its development into an international souvenir market.