Before 4th century B.C. Æ aes rude. An extremely large unformed cast bronze ingot. Approximately 65 x 23 mm, 141.75 g. Cf. Thurlow-Vecchi p. 15, pl. 2. Green patina with sandy deposits and some granularity. Quite nice and impressive.
From Thurlow-Vecchi, p. 15:
Comments on Aes Rudes and Aes Signatum. I: Aes Rude of Central Italy.
""Tradition assigned the institution of the Roman coinage to the period of the kings Servius Tullus and Numa. Pliny quotes Timaeus of Tauromenium in an inconsistent and confused account of the establishment of Rome's coinage and called these lumps of irregular weighing bronzes without official stamp or mark of value as Aes Rude or Aes Infectum.
Fifth century Rome did see the official valuation of bronze at equivalents of oxen and sheep, when in c. 450 the decemvirs codified the Roman Law in the famous 'Twelve Tablets' which recognized the bronze currency in use in central Italy (i.e., 1000 Asses = 1 ox, 100 lbs of bronze = 1 ox, 10 Asses = 1 sheep, etc).
A system of barter with copper objects had long existed in Central Italy where copper was plentiful and valued while silver was rare and gold nonexistent. The Italic population had produced Aes Rude from very early times and they are often found in hoards of votive deposits to divinities of fountains and rivers from the first half of the 1st millennium B.C. down to the end of the 4th century B.C. often along with Aes Signatum as in the Vulci hoard of 1828 and the Castelfranco hoard in Emilia of 1897. Emilia has produced considerable finds of Aes Rude which possibly indicates some local production but they have also been found in Campania, Southern Italy and Sicily.
Aes Rude weights are most irregular ranging from 8 g to over 300 g.""