"This ancient copper Ankh appears wrong side up. Found in the hands of Brotherhood of the Black Pharaoh who serve Nyarlathotep in his aspect as the Black Pharaoh.
Originally belonging to the Nephren-Ka, the dread Black Pharaoh of Ancient Egypt"
(This cult appears in the Call of Cthulhu role-playing game scenario Masks of Nyarlathotep.)
So this is another fictional artifact from my Call of Cthulhu games based upon the works of HP Lovecraft.
Made of polymer clay then painted copper and heavily treated with chemicals to patina and develop verdigris.
Download it to see the details.