One of two $20 Double Eagle coins is shown in this April 2014 handout photo provided by Odyssey Marine Explorations Inc May 5, 2014. The coins were salvaged during Odyssey's first reconnaissance dive to the SS Central America shipwreck site, which lies 2,
One of two $20 Double Eagle coins is shown in this April 2014 handout photo provided by Odyssey Marine Explorations Inc May 5, 2014. The coins were salvaged during Odyssey's first reconnaissance dive to the SS Central America shipwreck site, which lies 2,200 meters deep and 160 miles off the coast of South Carolina. REUTERS/Odyssey Marine Explorations Inc/Handout via Reuters (UNITED STATES - Tags: SOCIETY) NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. THIS PICTURE IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS
One of two $20 Double Eagle coins is shown in this April 2014 handout photo provided by Odyssey Marine Explorations Inc May 5, 2014. The coins were salvaged during Odyssey's first reconnaissance dive to the SS Central America shipwreck site, which lies 2,200 meters deep and 160 miles off the coast of South Carolina. REUTERS/Odyssey Marine Explorations Inc/Handout via Reuters (UNITED STATES - Tags: SOCIETY) NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. THIS PICTURE IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS

A middle-aged US couple from California is now several millions richer after deciding to auction off the 1,427 rare gold coins they unearthed in their backyard and discovered while having a leisure stroll with their dog.

Extracted in March 2013, the couple placed the 19th century rare gold coins on sale Tuesday night at Amazon and Kagins.com (here). The latter is a gold broker handling the sale.

Mid-day on Wednesday, half of the coins had been already sold for $2 million, broker Don Kagin said. A single gold coin - an 1874 $20 double eagle - sold for a whopping $15,000 alone.

However, the most valuable ones, which most definitely also comes with the higher price tags, have yet to be purchased. Kagin believed the more discerning collectors are still taking their time scrutinising the gold haul.

Experts believed the 19th century rare gold coins could fetch a whopping total of $11 million for the couple. It is so far the largest trove of buried treasure yet unearthed in North America.

"This is really the most significant find of buried treasure that's ever been made in North America," Reuters quoted David McCarthy, a coin specialist with Kagin's.

Named the Saddle Ridge Hoard for the area where it was found, the collection includes four $5 gold pieces, 50 $10 gold pieces and 1,373 $20 double eagles. They are in mint condition. The collection contains pieces struck from 1847 to 1894.

The couple, who will forever remain unidentified, said they found the gold near a tree in their back yard buried in eight cans.

Watch the video here of the Saddle Ridge Collection.

The couple intends to use the money generated from the sale to pay off their debts, while donating the rest to charities of their choice.