Bentonite for Dummies

Structure of montmorillonite clay

The Antisocial Network's staff geologist doesn't show up for work every day, probably because the poor guy has a consistent, pounding headache from all the doofus things nominees have to say on his favorite science. People who wouldn't even think of writing about chemistry or physics¹ seem to think it's OK to write about geology because every 5-year-old knows all about volcanoes and dinosaurs. That must be why Karize Uy tried to explain, "What is Bentonite?" to any unfortunates who happened to surf to WiseGEEK.com when googling that question.

If you know something about the stuff, you can see that there are germs of fact scattered throughout Uy's content. The problem, our geologist shared with us, is that it's pretty clear she found a couple of references and just did a half-fast job of spinning their content. That's probably how she came up with such weird "factoidalistic" statements as,

"Bentonite is a geological clay material that is mainly made up of a mineral group called montmorillonite. It is usually created from volcanic ash that has been disintegrated by water. Other minerals included in bentonite clay are aluminum, calcium, potassium, and sodium."

We aren't certain what other kinds of clay there are other than "geological"; but Karize did manage to get the montmorillionite fact correct. Just what "disintegrated by water" means is puzzling, but we suppose it's a reference to chemical weathering. That last is, frankly, hilarious: "aluminum, calcium, potassium, and sodium" aren't "minerals," they're elements. According to the wikipedia entry Uy appears to have attempted to reword, they're the major elements present in different classifications of bentonite. Uy wanders along, attempting to inform her readers that, "Geologists have estimated that the formation of bentonite can be traced as far back as 70 million years..."

...which probably surprises geologists who've identified bentonite layers more than 200 million years old, and then explains that,

"...the clay has settled in the lower layers of the earth’s soil and usually requires mining and quarries to be obtained..."

...which, we suppose, makes a crude sort of sense: after all, bentonite is mined (mostly in Wyoming, USA). We also loved Uy's attempt to explain swelling clays:

"...the clay’s particles that are shaped like plates and make for a larger surface area. The water then exchanges ions with the particles and the clay can expand and swell in size."

Water exchanges ions? With the "particles"? Really? Suffice it to say that the process by which smectites like montmorillonite expand is a bit more complex than "water... exchanges ions with the particles"!
The remainder of Karize's attempt to explain bentonite wasn't so science-rich, and she did a fairly workmanlike job of explaining common uses for the stuff, including cat litter and soap; though she has squat to say about its use in drilling mud. By that point, however the level of inaccuracy had already passed the Dumbass of the Day event horizon. That's two for Uy... bet there'll be more!

¹ Some of the scientifically illiterate freelancers, unfortunately, have no problem attempting to write about physics and chemistry...

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