CONCORDIA AVGVSTORVM
Bust of Tranquillina to the right, diademed, draped and set on crescent.
Gordian III standing left and clasping hands with Tranquillina standing on the right. Gordian III holding a scroll with his left hand.
Photo of a coin sold the 10/10/2017 by iNumis, Mail Bid Sale 38, lot 139, link to the sale: https://www.acsearch.info/search.html?id=4427695, link to their website: https://www.inumis.com/. Coin from a 20th century collection.
RIC 4C n °250 describes Gordian III standing on the right and Tranquillina on the left, it must be an error because I did not note any coin with this position for the characters. In addition, the coin illustrated on plate 3, n°19 shows Gordian III on the left and Tranquillina on the right. Unless the book describes another coin where the positions are reversed.