The god Aker, protecting the entrance of the Other World1, was depicted as the foreparts of two lions back to back representing the eastern and western horizons1. Amulets of Aker in carnelian or ivory are rare and were made in between Dynasties 6 (Old Kingdom) and 12 (Middle Kingdom)2
Carnelian L 1.2, H 1.0, T 0.4 First Intermediate Period? © The Trustees of the British Museum #EA57773
Carnelian with suspension loop L 2.1, H 1.9, T 0.6 Middle Kingdom Dynasty 11-12 Private collection DA
References
1Wilkinson R H. The complete gods and goddesses of ancient Egypt, 2003, Thames & Hudson, p. 176
2Andrews C. Amulets of Ancient Egypt, 1994, p. 90 and Figs. 4c and 67c