For golfers, the Golden Bear is none other than Jack Nicklaus, designer of courses, maker of 20 holes-in-one and winner, by four, of more majors than Tiger Woods.

But rockhounds have a Golden Bear to call their own: a gold nugget that, when turned just so, looks like a bear lumbering along on two feet.

Both Golden Bears are worth more than their respective weights in gleaming metal, but only one will be on display — along with the Moorpark mammoth unearthed in 2005 — during the Golden Bear Gem & Mineral Show taking place Friday through Sunday at the Ventura County Fairgrounds.

"It's considered unique and irreplaceable — or priceless," said Jim Brace-Thompson, secretary of the Ventura Gem & Mineral Society, which, along with similar groups in Oxnard, the Conejo Valley and beyond, is presenting the show under the auspices of the California Federation of Mineralogical Societies.

According to CFMS lore, the Golden Bear nugget was discovered in the 1850s by a 14-year-girl operating a sluice box at the Georgia Hills Mine in Placer County.

After her death at age 75, a family member was said to have used the nugget as collateral for a loan. When the loan went into default, the nugget changed hands. In 1940, it was purchased for $300 by the then newly formed CFMS.

The nugget measures about 2 1/4 inches high and 1 5/16 inches wide, and weighs 1 ounce, or 19.2 grams Troy. If you were using current per-ounce prices as your only guide, it would be worth about $900, said Brace-Thompson.

However, "collectors would cringe at the thought of melting down a nugget of this size and unique appearance," he added, noting the naturally occurring, crystallized gold triangles that dot its surface.

Typically on permanent display at the Los Angeles County Museum of Natural History, the nugget will make a rare trip to Ventura for the first CFMS show to be held at the seaside community in five years.

Also on view will be samples of California's state gemstone (the sapphire-blue benitoite), rock (satiny green serpentine) and fossil (Smilodon, aka the saber-toothed cat).

Organizers are calling the 69th annual tri-state convention the "Super Bowl of gem shows," with some 3,000 rockhounds expected to attend.

Among the attractions will be a children's activity area, hourly silent auctions, door prize giveaways and items offered for sale by dozens of dealers and vendors specializing in fossils, gemstone roughs, stone carvings, fine jewelry, lapidary equipment and more.

The three-day event also will offer jewelry-making and silversmithing demonstrations, and a series of illustrated lectures on topics ranging from petrified woods to something more out of this world: the "planetary geology of Jupiter and its moons."