Anonymous. 4th-3rd century B.C. PB cast aes formatum (38x36x13 mm, 91.94 g). Cast leaded bronze in the form of a cockle shell. Thurlow & Vecchi p. 20; Burgos P.28. EF, as made, green and earthen patina.
Called "aes formatum" by Haeberlin, this very rare bronze currency was a precursor to the issues of aes grave but later than aes rude.At over 90 grams, this is the largest I've handled in my 30 year career. The lead version of this type were commonly found at altars and were probably used as votive offerings.