Geodes for Dummy Earth Science Students

geode with smoky quartz crystals

When it comes to scientific information, a great many of the freelance posts we find at content farms tend to be lacking in some way or another. Much of it contains misinformation that arises from the writer's inability to translate technical terminology (usually in an attempt to avoid being charged with plagiarism). Some of it is... well, incomplete; mostly because the writer didn't know enough to consult multiple references. That's the variety we have today, a "science-y" post that only tells part of the story: eHowian Kathryn Hatter attempting to explain "What Is a Geode?"¹ for OurPastimes.com.

Hatter, a "veteran homeschooler" whose chief interests seem to be gardening and crafts, snapped this one up quickly. After all, geodes are kinda "crafty," no? Whatever... Kathryn jumps right in by telling her kids, err, readers, that

"A geode is a rock with a special surprise inside. From the exterior, a geode appears to be a boring round-shaped rock with little to capture one's attention. If a rock like this is broken open, however, it will reveal a center that is filled with colorful crystals."

The flowery little "special surprise" bit notwithstanding, Hatter's explanation is misleading: "colorful crystals" suggests a rainbow of hues, but most geodes contain white, gray, or colorless minerals. But hey, some of them have colored crystals. Oh, and Kathryn? You neglected to mention that the most interesting thing about geodes is that some of them are hollow. That word doesn't even appear in your post!
Hatter goes on to mangle the geology of geodes, passing along such misinformation as

• "Geodes are created when air pockets form in hot volcanic rock." – Many, if not most, geodes form within voids in limestone, which is not volcanic.
• "Over time, the crystals gradually form as water seeps in and out of the air pocket. The minerals contained in the water get left behind..." – Apparently the concept of precipitation was too hard to explain.
• "Geode crystals look different depending on the location in which they are formed." –  Ummm, actually, the crystals look different depending on the mineral(s) present. That's only indirectly related to the location, Kathryn.
• "Some of the most striking geodes are found in South America. These geodes have dark purple crystals in the centers and are called amethyst geodes." – Amethyst, a pale purple variety of quartz, isn't the most striking mineral found in a geode by far. Those are just the ones Hatter found for sale somewhere...
• "A very large geode was discovered in 1999 in Spain... The crystals in the center are white and some are over three feet long. It is hypothesized that the crystals formed millions of years ago when the Mediterranean Sea evaporated a great deal and left salt in the geode air pocket..." –  1) so much for "hot volcanic rocks," and 2) the crystals aren't "salt" (NaCl), they're gypsum (CaSO₄).

With homeschoolin' mamas like Hatter passing along half-witted pseudoscience like that, it's small wonder that kids today are growing up scientifically illiterate. Unfortunately, a substantial number of supposedly qualified teachers don't seem to have a much better grasp of scientific principles. After all, we've named several teachers the Dumbass of the Day...

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/about_5035986_geode.html

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