A rare $4 gold coin could possibly sell for $1.5 million dollars at auction on September 23rd. Paul Song, Director of Rare Coins for Bonham’s Auction House said that the rare $4 Coiled Hair Stella gold coin from 1880 contains six grams of pure gold and was never released to the public.

Song said the gold coin was designed to match the weight of foreign money from countries like France, Belgium and Switzerland. The idea was to make it easier for inter-country trading but the coin never received public support. Reuters reports that the rare $4 gold coin is considered one of the “white whales” of coin collecting.

Song then added,“At the end of the day, there was just not enough public support for it, and it became a political issue so it was basically a scrap heap of history, which also is what makes it so rare today. The 1880 $4 Coiled Hair Stella is one of the so-called white whales of the coin collecting world. They are so rare, they come on the market maybe once or twice, at most, every decade…That particular coin, there’s only 10 or 12 now, and most of these are in public institutions or private collections.”

Song told Reuters, “That’s an average lot value of almost $300,000 per coin. That may not be a Monet painting but in my world, that’s pretty amazing. It’s been a privilege to handle them, and they are gorgeous, just because they’re gold, perfectly struck and the designs are really incredible.”

Image via Bonham’s Auction House