Clay for Dummies (Minerals Week 2)

Oops, Elizabeth: I see iron...

It doesn't matter what the subject of a content-farm post is, there will eventually be someone who reads it and reacts. The reaction depends on both the stimulus and the person who reacts, but it can range from mild amusement to inchoate rage. Today's DotD candidate, an eHowian claiming the name Elizabeth Jennings, managed to stir a fairly mild reaction – "Whaaaaa?????" – in the Antisocial Network staffer who ran across the content she wrote at OurPastimes.com under the title, "What Is Primary Clay?"

Soil scientists and geomorphology geeks divide clays into two groups based on process: primary clays are those formed in situ through the weathering of minerals that are unstable at the Earth's surface. Secondary clays are primary clay that has been transported and redeposited somewhere else. It's that simple – as Jennings managed to say here:

"Primary clay is usually found in the same place as the feldspar from which it originated, while secondary clays have been transported by wind, water or both from their places of formation..."

...which is more or less correct (the "wind, water or both" bit is gilding the lily, we say). Elizabeth's problem, however, is that in order to collect her stipend from Demand Media, she had to pump out a lot more words. Not "information" and not "facts," mind you; "words."

Jennings met her goal with more than 430 words. In the process, however, she managed to mangle quite a few facts. We won't bother with her descriptions of the aesthetic qualities of clay and the potter's art, but we draw the line when it comes to bogus "science":

• "Feldspar, in turn, is the mineral name for a group of compounds formed from chemically bonded silica, alumina and one of the following: potassium, sodium or lithium." – Wait, lithium??? No, Elizabeth, it's potassium, sodium, or calcium. You're apparently confused by the woo-woo crystal set's habit of calling spodumene "lithium feldspar." It ain't feldspar: it's a pyroxene.
• "When water replaces the metals in feldspar, primary clay is formed." – Well, kinda; and kinda not. It's a lot more complex than "replaces," plus clays result from the weathering of more than just feldspars.

• "Because the weathering processes that move primary clay often introduce other elements, minerals and particles ('contaminants'), primary clay is rarely found away from its place of origin." – Idiot: as soon as it's transported (under this naming convention) it becomes secondary clay. Perhaps you're confused by the alternate term "residual clay"?
• "The most notable contaminant that does not appear in primary clay, but is present in virtually every secondary clay, is iron." – False: some clay minerals – kaolinite and halloysite, for instance – lack iron, but clay minerals of the illite group contain variable amounts of iron. That's what you get for trying to get science from a pottery website...
• "Known for its pure white, almost translucent color, rarity and difficulty to craft, primary clay (kaolin)..." – Sorry, Elizabeth, any clay can be primary. You're at some pottery website again, aren't you...

When it comes to questions about science, we strongly suggest that anyone wanting information perform their research at science-based sites. Perhaps that seems unfair to communications majors (and philosophy grads like Jennings), but trying to get science from what an artist understands of it is usually similar to that game of "telephone" we played as kids. Elizabeth did lousy research by going to "soft" websites, but as a result she did receive an award: she's now the Dumbass of the Day.

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SI - MINERALS