It is a medal.:
1821, Great Britain. OFFICIAL CORONATION MEDAL OF GEORGE IV. By Benedetto Pistrucci. AE 35mm. Obv: Laureate head of George IV facing left. Leg: GEORGIUS IIII D . G. BRITANNIARUM REX F . D. (George IV, by the grace of God, king of the British, defender of the faith). Rev: An allegorical coronation scene. Leg: PROPRIO JAM JURE ANIMO PATERNO. (Now in his own right with his father's mind). BHM 1070, Wollaston xv, Eimer 1146, Fearon 272.1.
The site I got that info from was asking $175 for one in XF for what that's worth to you.