Gil is the current standardized currency of Eorzea. It can be obtained by players by completing quests and levequests, defeating certain enemies, or selling various items to NPCs or on the Market Boards. The symbol representing Gil in text appears to be a mixture of an inverted G and a P, perhaps a reference to the abbreviation "GP" sometimes used in the franchise. Though the appearance of gil coins can vary by mint (and likely by denomination) the face on the coin icon in the User Interface is that of Nymeia, the Spinner, Goddess of Fate.
The currency now commonly referred to as “gil” was officially adopted by the city-states of Eorzea roughly one-hundred years ago, as a means to strengthen trade relations in the wake of the Autumn War. Prior to this, each city-state minted and regulated its own currency, which led to unpredictable exchange rates and prompted many traders to use ancient Allagan pieces in lieu of other coinage. Recognizing the wisdom of the practice (and desiring greater control over the money supply), the leaders of Eorzea announced the creation of new gil, and further decreed that its value would be standardized across all nations. Moreover, to help encourage adoption, it was designed in the image of its precursors.
Initially, as an expression of solidarity, these coins were to be engraved with images of the Twelve, rather than those of individuals beloved of a single nation. As time passed and the gil rose to prominence, however, the policy was relaxed, and the coin came to bear an ever increasing variety of motifs. Those minted to commemorate the reformation of the Eorzean Alliance are a notable example from recent years.