Hello David,
The mortar would make a heavy combat helmet.
Always handy when you get into conflict about how many peanuts should be used for peanutbutter
I saw the two toned wood also on Zanzibar about ten years ago and learned that most woodcarvings offered there where made in the Mombasa region.
But I can imagine that there are several kinds of two toned wood to be found in Africa. Although as far as I knowmostly in south and/or east Africa.
. I have a mortar from Gambia and that one is much more narrow and longer. So maybe there are certain models that can be placed in a region. Maybe someone who really knows the culture there can say something about the shape of the mortar.
