Passage 5.12.7
αἱ δὲ εἰκόνες αἱ τοῖς κατασκευάσμασι τοῖς περιφερέσιν ἐγκείμεναι, ἡ μὲν τοῦ ἠλέκτρου βασιλέως Ῥωμαίων ἐστὶν Αὐγούστου, ἡ δὲ τοῦ ἐλέφαντος βασιλέως Νικομήδους ἐλέγετο εἶναι Βιθυνῶν. ἀπὸ τούτου δὲ καὶ τῇ μεγίστῃ τῶν ἐν Βιθυνίᾳ πόλεων μετεβλήθη τὸ ὄνομα, Ἀστακῷ τὰ πρὸ τούτου καλουμένῃ· τὰ δὲ ἐξ ἀρχῆς αὐτῇ Ζυποίτης ἐγένετο οἰκιστής, Θρᾷξ γένος εἰκάζοντί γε ἀπὸ τοῦ ὀνόματος. τὸ δὲ ἤλεκτρον τοῦτο οὗ τῷ Αὐγούστῳ πεποίηνται τὴν εἰκόνα, ὅσον μὲν αὐτόματον ἐν τοῦ Ἠριδανοῦ ταῖς ψάμμοις εὑρίσκεται, σπανίζεται τὰ μάλιστα καὶ ἀνθρώπῳ τίμιον πολλῶν ἐστιν ἕνεκα· τὸ δὲ ἄλλο ἤλεκτρον ἀναμεμιγμένος ἐστὶν ἀργύρῳ χρυσός.
The statues placed within the movable structures, one of amber, represent Augustus, emperor of the Romans, and another one, made of ivory, is said to depict Nicomedes, king of Bithynia. From him also the greatest of the cities in Bithynia received a change of name, having previously been called Astakos. Its original founder was Zypoites, who, judging from his name, was likely of Thracian descent. Now this amber from which the statue of Augustus was fashioned—the sort that occurs naturally, found in the sands of Eridanus—is exceedingly rare and especially valued by men for various reasons; but that other amber is gold intermixed with silver.