Geodes for Hoosier Dummies

Geodes in stream bed

Though he's most often called upon to debunk some of the dumber claims of freelancers attempting to explain the oil industry or plate tectonics, the staff geologist can also address other, more prosaic geological dumbassery. We're thinking of the sort of half-witted attempts to translate semi-scientific verbiage into completely unscientific verbiage that Michael E. Carpenter pounded out for OurPastimes.com in a post called, "Where to Find Geodes in Indiana."

Carpenter's problem, we suspect, was that the insurance salesman turned freelancer tasked himself with removing what he considered "scientific jargon" from a couple of references that were already written for the lay public. That's where he came up with some fairly doofus information, starting with his introduction to geodes:

"It is believed that geodes began as crystals that were covered in silica. "

Well, no, that's not what either of Mike's references said. What they actually said was that geodes in limestone are thought to begin life as gypsum nodules (one reference described them as "cauliflower-like"), not "crystals," that were later coated with silica. Once he got that out of the way, Carpenter did little more than lift a list of Indiana counties where geodes are found. His problem, of course, is that all those counties he listed cover several hundred square miles, so Michael was forced to rework more verbiage:

"When searching for geodes, look along riverbeds, construction sites or other areas that have been eroded away... Geodes can also be found anywhere bedrock is exposed in the southern portion of the state... One of the most productive ways to find geodes in Indiana is to gain permission to hunt rock quarries."

So much crap, so little space to correct it! But we'll try:

• No, construction sites are not "areas that have been eroded away.."
• Geodes are not found "anywhere bedrock is exposed in the southern portion of the state," geodes are restricted to certain limestone formations, in particular the Harrodsburg Limestone.
• Carpenter conflated advice for general mineral hunting with geode hunting: you don't look for geodes in quarries!

Mike correctly pulled out the information that the best places to look for geodes in Indiana are in creek beds and road cuts, but he neglected to mention that the best geode accumulations are in one relatively thin limestone unit (the Harrodsburg Limestone), not randomly scattered across southern Indiana. That's because he had no idea what he was talking about.

Carpenter's problem, unfortunately, is a common shortcoming of Dumbass of the Day candidates. In fact, it's almost always exactly why they win our coveted award.

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