Fossilised incisor with imgur link - reposting for clarity and improved image sharing

Hi,

Found this in an old riverbed a few metres down through the layers of stones, gravel and sand whilst searching for gem stones. After much discussion and consultation with friends, have concluded the fossil to be an incisor, however, unsure if the incisor is of human origin, or earlier. Found in Central Queensland, Australia...

Images at http://imgur.com/a/Hk5YQ

Thanks for looking and your interest