Got a spare $US1m? A record beating ~9kg gold nugget is up for sale.

The Alaska Centennial gold nugget made headlines when it was discovered in 1998 near Ruby, Alaska, a town established in the late 1800s as the result of the Klondike Gold Rush.

The nugget’s size is astonishing: larger than a softball, or about the size of a child’s head.

The man who found it was Barry Clay, who, so the story goes, discovered the giant nugget while pushing dirt with his bulldozer along the shores of the Swift Creek Mine.

Clay is said to have buried the nugget near a tree, buying time until he decided what to do with his remarkable find.

The current owner purchased the rock directly from Clay, and it has been in the same family for more than two decades. This auction marks the first public offering of the heralded, museum-quality piece.

The fact that the Alaska Centennial gold nugget exists at all makes it all the more exceptional, Craig Kissick, Director of Nature and Science at Heritage Auctions says.

“Fewer than 50 gold nuggets over 250 ounces exist as gold in nugget form… (it’s) inherently rare; gold nuggets of massive size, even more so,” he says.

“The majority of gold mined is refined.

“A one-ounce gold nugget is even more rare than a five-carat diamond.”

The Dec. 8 Nature and Science Signature Auction – live in Dallas and online — will feature more than 300 lots of one-of-a-kind objet d’art pieces, “including two single crystals of gold that were of such a significant find, astonished mineralogists studied them for years”.

One of the native gold crystals up for auction.