Rare 1776 continental dollar coin found inside toffee tin to be auctioned

One dollar will be worth a lot more than that — as a rare 1776 continental dollar coin is set to go to auction next month.

Wotton Auction Rooms told CBS News in an email that one of its clients brought in their collection to be sold, and the haul contained several 18th and 19th-century items. Auctioneers for the Gloucestershire, England-based auction house sorted through the hundreds of pieces that were brought in the toffee tin when they found the coin near the bottom. The coin initially "looked rather dull and boring," the auction house said.

"It was one of the last objects to be examined. Once work started, we thought that the chances were that it could well be a copy, although everything else within the tin had been genuine and of a very good standard," Wotton Auction Rooms said.

The auction house sent the coin to the NGC numismatic guarantee company for authentication — and the results confirmed the coin's authenticity, Wotton Auction Rooms said.

The continental dollar was the first pattern coin struck for the United States. Believed to be designed by Benjamin Franklin, the continental dollar concepts were translated into coins by Elisha Gallaudet, a New York engraver. Gallaudet was thought to have made them at a makeshift private mint in New Jersey, the Smithsonian Museum said , and the coins were issued in silver and pewter.

The silver versions of the coins are extremely rare and only two are known to exist, according to the Professional Coin Grading Service , a rare coin grading company. About 20 pewter continental dollars exist in mint condition, said PCGS. In 2008, a pewter continental dollar was auctioned for the record price of $264,500. In 2015, a silver continental dollar was auctioned off for a record $1,527,500.

The recently discovered coin is set to be auctioned on October 3, said the auction house, and is estimated to go for £20,000 (about $26,360) to £30,000 (about $39,540)