This seems also to be a very rare amulet1
Faded blue glaze H 1.8, W 1.3 Late Period
Roemer-Pelizaeus Museum #6191
From Sotheby’s London, part of lot 150b
23 May 1991
References
1Andrews C. Amulets of Ancient Egypt, 1994, p. 96 and Fig. 92h (British Museum #EA50152)