How to Identify the Nero Sestertius

What This Coin Is

This large bronze, technically orichalcum (a brass-like copper-zinc alloy), sestertius was struck under Nero as part of the base-metal coinage system that circulated alongside silver denarii for everyday transactions.

Obverse Design

The obverse shows a laureate or radiate-crowned head of Nero facing right, with a portrait that becomes noticeably heavier and fuller-necked in later issues. The surrounding legend gives his name along with his accumulated imperial titles.

Reverse Design

Several celebrated types debuted under Nero, including a detailed harbor scene representing the Port of Ostia with ships and a reclining figure, the Temple of Janus shown with closed doors to signal peace, a seated Roma, and a standing Annona holding a modius and cornucopia. The letters SC (Senatus Consulto) appear in the field or exergue on most types.

Size, Weight, and Metal

This is a notably large Roman coin, measuring roughly 34-38mm across and weighing around 25-28 grams. Struck in orichalcum, it shows a warm golden-yellow color when fresh, aging to a darker brown or green patina over time.

Mint Marks and Where to Look

There is typically no separate mint abbreviation. The SC in the reverse field or exergue simply signals senatorial authorization of bronze coinage, standard practice under the early Empire rather than an indicator of a specific mint location.

Telling It Apart From Similar Coins

Distinguish this from the smaller dupondius, also orichalcum but roughly half the diameter and weight, and from the as, which is pure copper with a more reddish-brown color and smaller size. The harbor scene and Temple of Janus reverse types are distinctive enough to identify a Nero issue once recognized.

Grading at a Glance

Because of its large flan, strike centering and legend completeness are easy to assess at a glance. Look for even wear across the portrait's high points, such as the hair and cheek, and the reverse scene's architectural or figural details. A natural green, brown, or "chocolate" patina is desirable and expected, not a flaw.

Authenticity Red Flags

Cast fakes often show a grainy, pitted surface and a visible edge seam, unlike the crisp flow lines of a genuine struck coin. Be cautious of artificially applied "fake patina" that looks uniformly painted on rather than naturally variegated, and verify weight and diameter against genuine examples, since undersized or underweight pieces are common in reproductions.