Engraved on a thin pale amethyst of round shape is the arresting frontal portrait bust of a man wearing the toga, the quintessentially Roman uniform for all men involved in public life.
Although the physiognomy of this gem portrait is not specific enough for a definite identification, the facial features and close-cropped hairstyle of this middle-aged man are reminscent of Julio-Claudian portraits, such as the sardonix cameo of a Julio-Claudian prince formerly in the Sangiorgi collection, see Masterpieces in Miniature, Christie's, New York, 29 April 2019, lot 33 for a full bibliography.
Even the round shape of the gem points to a production date around the late 1st Century B.C. or early Imperial, see a frontal male portrait bust in carnelian in the Kunsthistorisches Museum, Vienna, inv. no. Antikensammlung, IXb 727, or the amethyst portrait of Pompey the Great now in The State Hermitage Museum in St. Petersburg, inv. no. 1468.