Contemporary African brass mask. It appears either to have been made purposely without any hole or loop for hanging or to be miscast. 

This mask was made by the ancient traditional lost wax casting process where the object is first shaped of bees wax then covered with a sand & clay investment. This unit is dried and then baked so the investment hardens and the wax runs out leaving the space into which the molten brass is poured. Once cooled the investment is removed, broken off, never able to be used again, to yield the object so cast. Every single object of this type, no matter how small, is made this same way, one by one, by hand. 

This mask measures 1 1/8 x 1" (3 x 2.5 cm)