I have taken these photos of spoons and cutlery in a shop in Hội An, Central Vietnam.These spoons are made of some gastropod shells, most probably of green turban Turbo marmoratus. With the shell length up to 20 cm (or up to 25 cm) it is the largest species of the family Turbinidae. It’s distribution is Indo-Pacific. As of 1974 it has been listed as a “common” species. The shell is commercially important as a source of nacre (mother of pearl) and it is the most important commercial species of Turbinidae in the tropical Indo-West Pacific. It is intensively harvested and exploited in some countries. Many of its populations has been reduced.
Dance S. P. (ed.) (1974). The Encyclopedia of Shells. Blanford Press, ISBN 0713706988, pages 52-53.
Dwiono S.A.P., Pradina & Makatipu P.C. (2001) Dwiono, S., & Pradina, M. P. (2001). Spawning and seed production of the green snail (Turbo marmoratus L.) in Indonesia. SPC Trochus Information Bulletin# 7. Poka–Ambon, Indonesia, 7.
Turbo marmoratus Linnaeus, 1758. https://www.sealifebase.ca/summary/Turbo-marmoratus.html accessed August 15, 2019.