Gigantic Gold Nugget to be Auctioned in San Francisco Tomorrow

It is known as the "Butte Nugget" because of where it was discovered, in the mountains of Butte County, Nevada.

The huge gold nugget was found on public land last July.

Gold prospecting is legal on most public lands.

For security reasons, the prospector wishes to remain anonymous. And we don't blame them. The nearly 6 pound gold nugget is expected to sell for more than $350,000 at the San Francisco Fall Antiques Show.

The nugget is being auctioned by Don Kagin, owner of Kagin's Inc, a numismatic firm. Kagin said he has made extra effort to ensure the authenticity of the find after he was tricked in 2011 by what was then believed to be the largest Mother Lode nugget of the modern era, weighing more than 8 pounds.

That nugget, dubbed the "Orange Roughie" was later discovered to be from Australia, and not an original, historic California Gold Rush find. The perceived historical value of that nugget drove the price up and when it was discovered to actually be a modern find from Australia, Kagin was forced to buy the nugget back (for $460,000) and resell it at a much lower price.

During the gold rush of the 1800s, several gigantic gold nuggets were discovered, including a 58-pounder called the Magalia Nugget, but nearly all of those have been melted down.

David McCarthy, the senior numismatist at Kagin's worked to verify the find by travelling to the location where it was dug up, but even he doesn't know exactly where it was. He had to be blindfolded before the prospector would take him to the spot. He described it as "rugged."