Outdoors

A successful agate hunt yields beautiful rocks

Wildside column: Mike Hunt offers tips to finding 'gems'

This agate, with most of its exterior host rock intact despite 1 billion years of buffeting, was the day’s best find during an agate hunt on March 31 in northeast Iowa. (Mike Jacobs)
This agate, with most of its exterior host rock intact despite 1 billion years of buffeting, was the day’s best find during an agate hunt on March 31 in northeast Iowa. (Mike Jacobs)
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In a full day’s search on the last day of March, Mike Jacobs of Monticello and I found 121 agates.

That seemed a lot to an amateur like me, whose agate hunting has been largely confined to looking down while walking from one fishing hole to another.

To Mike, a serious rock hound, it was a successful hunt, even though we didn’t find any of the “pounders” — agates weighing a pound or more — that would have rendered the day especially memorable.

Our find of the day was an agate that was still largely encased in its host rock, which seemed almost miraculous given the unknowable number of floods and glaciers that have pounded Lake Superior agates since their formation 1 billion years ago.

Rock hounds look forward to hunting after spring floods have scoured and rearranged streamside rock bars, exposing long-hidden gems.

With clear skies and a bright sun to illuminate the search field, anticipation ran high as Mike and I launched his kick boats in a northeast Iowa stream bearing the fresh wounds of a recent flood.

As we combed one rock bar after another, I could not help wondering how many non-agates lay within our scrutiny.

Mike would not hazard an estimate, while I, a longtime venturer of wild guesses, put the ratio of agate to non-agate at somewhere around 1 to 100,000.

Of course that does not mean you have to actually focus your eyes on 100,000 rocks to find one agate.

To maximize efficiency, rock hounds scan for key agate indicators as they stroll methodically across a stone-strewn stream bank.

As my mentor taught me last Sunday, translucence is at the top of the list followed closely by color and the presence of pit-marked surfaces.

Hardly ever will your eye alight upon the colorful layered bands most often associated with agates.

Among the most common agate impersonators in Iowa are chert and jasper, both of which often share the pink-red-orange-brown-maroon color spectrum in which most Lake Superior agates fall. Unlike translucent agates, however, they are opaque.

Sunday’s bright sun, which imparted a subtle glow to the translucent agates, helped us quickly distinguish between them and pretenders.

We walked side by side so I could benefit from Mike’s tips. Often he would announce he had spotted an agate so I could practice my skills at finding it.

On at least two occasions, to my considerable embarrassment, he pointed out fairly sizable and obvious agates next to my footprints in the sand.

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In my one “aha!” moment, when I found one next to a hole created as Mike dug an agate out of the sand, he said, “I left that for you as a ‘trainer.’”

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