Gold Argates are rare drops from monsters in The Deadlands, Space of Pilgrimage and Under Crespo Main. Gold Argates are mostly farmed by killing the Nymphs in Draco Desert. There are 2 Nymphs in Draco Desert and each drops 6 gold argates.
Gold Argates also drops from all bosses in Tower of Spell dungeon (higher floor = better drop). Tower of Spell is the recommended place for new players to farm Gold Argates.