Pearl shell used as a knife.
A shell that is used in very nearly its natural form is a kind of pearl shell that grows along creeks through the mangrove swamps. The shell is only very slightly curved and it is for this reason that it is selected as suitable. The weak edge or lip of the valve is broken away, and the edge is then slightly ground on a stone. This implement is used by women for slicing yams and certain other vegetables such as some kinds of seeds when they are being prepared for food. Brown (1922) The Andaman Islanders. Page 447.