Julia Domna, AE20 of Serdica, Thrace.

IO DOMNA AV, draped bust right.
CEPDWN, Serpent rising from altar, head right. 

Hristova & Jekov 12.17.47.2 (this coin); Varbanov 1986. 
Near VF, brown patina.

From the J.P. Righetti Collection, 9412.
CNG Auction 226, Lot: 351. Sold for $60. 
with permission of cngcoins.com