Dubbed the ‘Americus Australis,’ it weighs ore than 11,800 carats and is one of the largest gem-quality opals in existence, according to the auction house that handled the sale.
JUNEAU, Alaska — A gemstone describled as one of the largest gem-quality opals in existence has been sold for $143,750 at an auction in Alaska.
The opal, dubbed the “Americus Australis,” weighs more than 11,800 carats, according to the auction house, Alaska Premier Auctions & Appraisals.
It has a storied history. Most recently, it was kept in a linen closet at a home in Big Lake, north of Anchorage, by Fred von Brandt, who mines for gold in Alaska and whose family has deep roots in the gem and rock business.
The opal is bigger than a brick and is broken into two pieces, which von Brandt said was a practice used decades ago to prove gem quality.
Von Brandt said the stone has been in his family since the late 1950s, when his grandfather bought it from an Australian opal dealer named John Altmann.
Von Brandt said that, for decades, the opal was in the care of his father Guy von Brandt, who decided it had been “locked up long enough, that it’s time to put it back out in the world and see what interest it can generate.”
“He entrusted me to figure out which direction we wanted to go to part with the stone,” von Brandt said.
He said his family, with roots in California, exhibited the stone at gem shows for years, until the early 1980s. His father then branched out into furniture and displayed it at his shop. Guy von Brandt eventually moved to Oregon and kept the stone “kind of tucked away” for many years, his son said.
Von Brandt said he brought it with him to Alaska over a year ago as he weighed the best approach to a possible sale.
Nick Cline, a partner and appraisal specialist with the auction house, said the family has documentation of the provenance of the opal. As part of his research, he contacted Fiona Altmann, granddaughter of John Altmann and general manager of Altmann + Cherny in Sydney, Australia.
Altmann said her grandfather, in his business dealings, made regular trips to Europe and the United States.
The auction house said the stone was discovered in the same field in Australia as the opal known as the “Olympic Australis,” which weighs 17,000 carats and is on permanent display in Altmann’s shop. The Olympic had been among the stones that John Altmann and partner Rudi Cherny acquired in 1956, according to Altmann’s company.