I purchased this in Thailand, The woman selling it told me it was an elephant tusk, but based on the size and the price i paid that seems unlikely. I tried comparing to hippo teeth and boar tusks, but didnt look the same.
There is a little hole that has been forming over the last few years. It was not there at the beggining but every few months i shake it and more powder falls out like sand
This is an interesting one and what I would classify as a forgery, but as it is still made from part of an animal perhaps more interesting. The end of the structure looks like the joint surface of a long bone, the two which look most like this are a tibia and metatarsus of birds. There seems to be two joint surfaces sitting side by side to form a hinge joint. Both of these long bones are 'hollow' in that they contain trabecular bone at the ends (just under the joint surfaces). Usually this hollow part extends the full length of the bone but occasionally the centre of the shaft is solid. If you were able to only select bones which were solid in the center of the shaft you could carve them to create this item. Alternatively you could insert some thing inside the hollow bone to fill the hole. Have a really careful look at the 'sharp' end and see if it looks like a tube of bone with something stuck inside and then carved, it may be very difficult to tell if the forger is skilled.