Understanding the political importance of the royal portrait, Alexander the Great created a distinctive representation distinguished by his long, flowing, leonine hairstyle. Although he died in 323 B.C., portraits of him remained popular for centuries. The Hellenistic rulers who succeeded Alexander often used these portraits to show their ties to him and to demonstrate the legitimacy of their right to rule.
This gem from the first century B.C. is probably just such an example. The possibility remains, however, that the figure is not Alexander. Some Hellenistic rulers incorporated elements of Alexander's portraits, especially his hairstyle, into their own portraiture.