Trobriand Island Stone Axe head

I taught in Papua New Guinea for a number of years and travelled extensively with groups of students as part of my work. A Trobriand Islands family who I came to know very well gave this wonderful item to me in 1989. They explained its significance as a trade item, which they had acquired through a 'bride price' ceremony many years earlier. It is quite obviously an axe head, but has undergone an interesting transformation of usage from a simple tool to a valuable currency due to the lack of any solid stone on these corral islands.