JUNEAU, Alaska (AP) — Nick Cline gets calls about all kinds of items people want to sell through the Anchorage auction house where he works. But he was caught off-guard by a call he got last fall from a man saying he had "one of the largest opals in the world."

"I was extremely skeptical but extremely excited," said Cline, a partner and appraisal specialist with Alaska Premier Auctions & Appraisals.

According to the auction house, the opal, dubbed the "Americus Australis," weighs more than 11,800 carats and is one of the largest gem-quality opals in existence. It also has a long history.

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