The ancient Greek states did not mint many pieces of gold, and when they did, they produced usually only small coins. This coin (which will be auctioned soon by Harlan J. Berk) is the exception. Struck in honor of Arsinoe II, sister and wife of Ptolemy II, it weighs 27.72 grams and has a diameter of approx. 28 mm. It is a Mnaieion, equivalent to 100 drachmas of silver.
This extraordinary coin was not, for sure, used for everyday commercial exchange. Because of its enormous value, it was a good way to treasure wealth. This unusually large coin may also have had, at least in part, a ceremonial function related to a festival in honor of Queen Arsinoe, who was deified in her lifetime.
About three years ago, a treasure of Ptolemaic gold coins appeared on the ancient coin market, causing prices of coins like this one to go down, so the estimated value for the auction of this piece is "only" $ 12,000.