Where does one draw the line between art and artifact? Is it when the materials are deemed semi-precious or rare? Is it when the object is rare or singular? Is it when said object is decorated or designed in such a way as to be aesthetically pleasing rather than just useful? In this case, I think the boxes ticked are material used (nephrite) and the type of axe (flat axe, which is more aesthetic and less useful than a curved axe in the Neolithic).