Outdoors

Don't judge Iowa's state rock by its cover

Wildside column: Cracking open a geode is like 'opening a Christmas present'

Dazzling mineral crystals line the interior of this cracked-open geode. (TJ Ramsey photo)
Dazzling mineral crystals line the interior of this cracked-open geode. (TJ Ramsey photo)
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Iowa’s state rock, the geode, illustrates the adage that “you can’t judge a book by its cover,” said Marv Houg, president of the Cedar Valley Rocks and Minerals Society.

“It’s a great teaching tool for kids — that something homely on the outside can be beautiful on the inside,” said Houg of Cedar Rapids, a rock collector for the past 45 years.

Houg and other rock hounds will be displaying parts of their collections at the society’s upcoming annual show at Hawkeye Downs, whose theme this year is “Geodes: Iowa’s Mysterious State Rock.”

Geodes must be cracked open to reveal their inner beauty — an act attended with great anticipation by the cracker and onlookers, said TJ Ramsey of North Liberty, who enjoys cracking geodes during public presentations.

“People are eager to see what’s inside,” said Ramsey, who has been hunting geodes for half his 42 years.

“It’s like opening a Christmas present,” Houg said.

Apart from the stone’s intrinsic beauty, Ramsey said he enjoys finding them.

“It’s like a treasure hunt,” he said.

The word “geode” derives from the Latin for “earthlike,” a reference to their typically spherical shape. In recognition of its prevalence and beauty, the Legislature in 1967 declared the geode Iowa’s official state rock.

Houg and Ramsey do most of their hunting within 50 miles of Keokuk, the center of one of the world’s most productive geode collecting areas.

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That region was once a silt-filled shallow sea basin ideally suited to the formation of geodes, said Ray Anderson, a society member and retired geologist.

Anderson said geodes form in a three-step process occurring in soft sediment over as much as 300 million years. It begins with the accretion of layers of stone around a nucleus, followed by the dissolution of interior layers that are then replaced by crystalline growths within the cavity.

Houg and Ramsey find their geodes along streams in the region — which includes parts of Iowa, Illinois and Missouri — and dig them out of exposed shale layers in the Warsaw Formation, a 340 million-year-old layer of rock.

Houg said he once dug up a 175-pounder, one of the largest geodes he’s seen, and once collected 750 pounds of geodes in two days.

Ramsey said his biggest geode topped 200 pounds, and his most productive day occurred along Missouri’s Fox River, when he and his dad filled a 19-foot canoe with an estimated ton of geodes.

While prime specimens can fetch $1,000 or more, Ramsey said he values the stones for the experience of finding them.

“You can go buy them, but they mean more when it’s your personal thing that you found,” he said.

Though Ramsey sells geodes on his website (www.firstcrackgeodes.net), his many favorites are not for sale.

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As many as 4,000 are expected to attend the show at the Hawkeye Downs Expo Center, which runs from 8:30 a.m. to 6 p.m. March 23 and from 9:30 a.m. to 5 p.m. March 24.

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