This is a stone tablet created for the production of the 1994 popular Kurt Russell sci-fi film Stargate.
Pieces such as this can be seen throughout the film; the tablet is made of clay, is quite big and has been crafted and painted to resemble an ages old stone that has been broken on both sides from a much larger piece. Also in the center of the tablet is a carving of a seated figure who is sitting above raised hands and below the sun.
COA: Prop Store of London