Roadside Geology of Missouri Published!

Ironically… when I last wrote, it was to briefly rhapsodise on my fondness for the Roadside Geology books. It was a paean, perhaps even a tiny bit of a love letter.

One of the things that has been missing from that series, however, has been a volume for the state in which I reside, Missouri. I have known for a couple of years now that a volume was in the works, but, like trying to see the Ring Nebula in the eyepiece of a six-inch reflector, I assumed that by now, if you looked too hard for it and tried to stare directly at it, the book would remain stubbornly invisible.

Spencer-Roadside Geology of Missouri

Roadside Geology of Missouri, by Charles Spencer. Image Credit: Mountain Press

No more. It’s officially listed on Mountain Press’ website. Don’t just take my word for it: look.

The author, Charles Spencer, is a local consulting geologist and regular fixture at the Kansas City Gem & Mineral Show, among other places. I’ve spoken with him a couple of times about the book, and he was always wryly humorous about the prospect of it ever seeing the light of day. However, now it’s out, and, assuming that it is actually shipping, Roadside Geology of Missouri will be just in time to be a big hit at the Kansas City Gem & Mineral Show, which is just two weeks away.

My copy is already on order, so I haven’t read it yet, but expect a thorough review as soon as I can get my hands on it.


Roadside Geology

Slightly off-topic, but I wanted to write something quickly, since I’m still stuck writing about talc. It’s harder than it looks, this lark.

Following some links and ending up at, I saw something that I hadn’t seen before which made me smile. An imbedded link, for Mountain Press’ long-lived series, Roadside Geology. Awww.

Roadside Geology of Arizona

Roadside Geology of Arizona, published by Mountain Press.

Not wanting to appear to be just a vulgar shill for the publishing industry, let me just say that my memories of these books, with their bright, primary-coloured covers, go back to when I was fairly young, and my father was reading through an early edition – probably of the Arizona volume, if I had to guess. I’ve been around these books for a long time, and have grown to like them very much.

If I had one complaint about the series, it would be summed up in four words: more volumes, more quickly. The volume on Missouri has been promised for at least a year now, with the publication date continually being pushed back. I know that times are difficult, economically, but I’d really like to be able to drive around and read that book (and put a couple of dollars in author Dr Charles Spencer’s pocket, he’s a decent sort who I’ve bumped into for years now at the Kansas City Gem & Mineral Show). It’s also my habit now to pick up volumes, if they’re available, for states that we’re going to drive through on holiday. Last summer, that meant my copy of the Nebraska volume (now oddly out of print, it seems), Wyoming, Utah, and Colorado. I may not necessarily read everything in advance, but the books are a great sort of general reference whether you’re planning your trip or find yourself parked along the road somewhere, staring at the cut, and wondering “what the hell is that?”, in that way that the geologically-minded tend to do.

Do you live in a state for which one of the volumes has been published? How useful is it? Is there a better option? I’d like to know, as I suspect that there will be more driving holidays in my future, starting this summer, with a return trip to the San Francisco area that may include one or two lengthy detours…

Letter to the Editor

My original intention with this post was to just post a quick, informational link to the current issue of Rock & Gem magazine. Then, however, I was distracted. So distracted, in fact, that a letter seemed warranted. It will explain everything:


To the Editors,

I have subscribed to Rock & Gem for roughly two years now. As a science writer, avid mineral collector, and sometimes geology educator, I have found your magazine’s more conversational tone and more generalist stance to strike a good balance between publications obviously inclined toward professionals in the geosciences and the community of interested amateurs.


One of the features which I have generally been pleased with has been the ‘Rock & Gem Kids’ section, which I have shared with my own children. Obviously, interesting and educating the potential next generation of amateur lapidaries, mineralogists, and geologists is an important task. Kids are naturally interested in these things, as I always find when I give talks to school-aged children (which, in fact, I did just yesterday). They are often hungry for knowledge that they simply don’t get in school.


That is why I was frankly appalled to read the current ‘Rock & Gem Kids’ section discussing ‘Kansas Pop Rocks’ (February, 2011). No, it was not author Greg Sweatt’s line about throwing them into the fire until they exploded, although that was certainly questionable. Nor was it even the remark about how the pyrites are believes to have formed around fossil shell, bone, or tooth (I could find no citations for this, but it would be conceivable in some cases). Rather, what I am referring to is this:

“Rare, perfect pop rocks sell for big dollars as metaphysical stones, as they do emmanate energy, and people sensitive to that energy value them as healing stones.”


Who, precisely, proof-read this article? If you hold to any pretense of being even a remotely scientific publication, they merit a stern talking-to, if not outright sacking. And your author, Mr Sweatt, should be cautioned against putting nonsense like this in his articles.


Claims of “energy emmanation” are often made by those with more metaphysics than science in mind, without any clear understanding of what that “energy” might be, or how it is “emmanated”. Funnily enough, when materials which do “emmanate energy”, such as uranium and thorium-based minerals, or fluorescent minerals exposed to UV radiation, are discussed, these same people are often strangely silent.


Pyrite Concretion, Niobrara Chalk Member, Western Kansas

A pyrite concretion. Watch it closely. Did it move? Wait – did it wink at me just then? No, it didn’t. Photo Credit: Personal Collection.

Let’s be clear: these pyrites don’t emit energy. Not at all. Not one iota. I have one sitting on my desk right now. It is roughly ovoid, about three centimetres in diametre, and a sort of dark bronze colour. It doesn’t glow in the dark. It doesn’t trigger a Geiger counter. It refuses stubbornly to fluoresce. It is not magnetic. It is neither unexpectedly warm nor unexpectedly cold to the touch. It interferes with neither my computer, my mobile, nor my landline telephone. In short, it emmanates no energy whatsoever in any expected sense. If you want to claim that there is an “energy emmanation” from one of these stones, then you’d better be prepared with your data. Show me your experimental method. Demonstrate your hypothesis, quantify and qualify the “energy” being emitted. Why? Because that is how science works.


Why does this bother me? Simply this: because as a publication dealing with rocks, minerals, and gemstones, Rock & Gem sets itself up as a trusted source for science information. And in that single statement cited above, your editorial stance has been shown not to be scientific. That makes it very difficult for me to be confident in your publication as a trusted source. Remarks like the one above about “energies”, even if they are just meant as “a bit of fun”, have no place in discussions of the real world.


I would point readers interested in further clarification to the recently revised Second Edition of Rex Buchanan’s Kansas Geology (University of Kansas Press, 2010) and to D.E. Hattins 1982 paper ‘Stratigraphy and depositional environment of the Smoky Hill Chalk Member, Niobrara Chalk (Upper Cretaceous) of the type area, western Kansas”, Kansas Geological Survey Bulletin 225 (which sadly doesn’t appear to be available online at this time). Kansas County Bulletins published by the KGS can be found here, and Gove County, as well as other counties where the Niobrara chalk is in evidence, is represented in past publications which are free for all to read.


Sincerely yours,
Hexagonal Dipyramidal
So that’s how I spent my morning. Nothing like a letter to the editor to make one hungry for a bit of breakfast and the wine of the vanquished.

Minerals in the News: Calcite… and Invisibility!

The other night, I was scrolling through my feed reader (and honestly, I was trying to go to sleep) when I saw this story: Using Special Crystals, Researchers Make a Paper Clip Invisible. After reading a headline like that, it’s a little harder to go to sleep, especially when you find that your life-long dreams of rendering paper clips invisible are within a whisker of becoming reality.

The suggestion that these were “special crystals” in the article’s headline was somewhat surprising, given that they were described as calcite, which is one of the most common minerals in the world.  This consternation is borne out by the article’s content, which states that to render an object invisible:

“In both experiments, researchers had to finely tune their crystals—they’re technically composite crystals, as the researchers basically glue together two crystals with opposite crystal orientations—then placed them over small but entirely visible objects (MIT used a small metal wedge the size of a peppercorn; Birmingham went bigger, concealing a paperclip). “

In other words, naturally occurring calcite crystals were modified and used to precisely refract visible light. Clearly, this is more difficult than simply putting one Iceland spar on top of another and seeing something disappear (try it for yourself the next time that you have a couple readily to hand – there are obviously other mitigating factors). But it is a remarkable discovery.

Calcite Under a Green Laser

An Iceland Spar calcite crystal is subjected to the light from a green astronomical laser. Note the beam path in the crystal. Photo Credit: Personal Collection.

The optical properties of some crystals of calcite, specifically, the iceland spar rhombohedral crystal, are well-documented and thoroughly understood. When calcite crystallises in this particular form (one expression of the trigonal hexagonal scalenohedral (32/m) form), the planes within the crystal cause light to be refracted. Depending on the power of the light source, a projected beam of light fired through calcite, like that of a green astronomical laser, can result in the beam being spread out at regular intervals having been refracted along the crystal’s internal planes. When the crystal breaks light travelling through its structure, this is known as double-refraction, or birefringence.

The property is also well demonstrated by simply placing the crystal over some text, and noting the optical effect:

Text from a label doubly-refracted by an Iceland Spar calcite crystal. Photo Credit: Personal Collection.

A fossil impression of a trilobite head and upper thorax, Cambrian Era, House Range, Utah. Photo Credit: Personal Collection.

Calcite is also known to have acted as a component in the eyes of trilobites, a now-extinct arthropod species which dominated the planet for approximately two hundred and fifty million years, from the Cambrian through the end of the Permian. These complex lenses are one of many interesting features of this fascinating and long-lived group of creatures. Interestingly, the use of calcite in optical structures persists into the modern day, in the brittle star species Ophiocoma wendtii.


The rhombohedron is one particular expression of the crystal form of calcite.  Others are representative of varying conditions of temperature and pressure under which the crystals have formed.  For example, a specimen like this one from Dal’Negorsk, in Russia, is not only differently crystallised, but faintly fluorescent:

Calcite crystal cluster, 7 x 4.5cm, Dal'Negorsk, Russia. Photo Credit: Personal Collection

Calcite crystals on matrix, Somerset, England, 7 x 3.5 cm. From the same cave system which produced the "Flos Ferri" calcites (qv). Photo Credit: Personal Collection.

And, interestingly, this English calcite from the same cave system in Somerset which produced Flos Ferri aragonites exhibits an unusual expression of the 32/m form. In this case, though, the calcite is not fluorescent, for reasons which I will try to describe at length in a future posting. Interestingly, English fluorites from more northerly counties, including Durham and Cumbria, are famous for their fluorescence, the regional geology being significantly different. Again, fluorite will be the topic of another, future posting.

Calcite crystals overgrowing earlier (orange-brown) dogtooth calcite crystals. Overall size 6.5 x 5cm, Reynolds County, Missouri. Photo Credit: Personal Collection.

As I mentioned, calcite is one of the most common minerals in the world, and it occurs in a number of very interesting forms. In northern missouri, it is also one of the few minerals to be found in the local sedimentary rock.  In fact, it is common throughout the state, being found in quantity in the lead and zinc deposits of the Tri-State Area, in the Pennsylvanian-era limestones of the north, and in the east, in Reynolds County and elsewhere. To find that such a material now has an added utility and scientific value is interesting and gratifying, in the least.

Earthquake Weather

Although this is a blog about mineralogy, as it – and I – are based in Missouri, I couldn’t resist posting a link to this article from the Carthage Press, February is Earthquake Awareness Month in Missouri, because it made me smile for a moment.

New Madrid Historical Society

A delightful ante-bellum home from New Madrid, Missouri. Photo Credit: New Madrid Historical Society.

Typically, when thinking of the more earthquake-prone states in the United States, Missouri does not come to mind. But nearly two hundred years ago, beginning on 11 December 1811 and continuing through 7 February 1812, several of the most vigorous earthquakes recorded in the young United States struck in the New Madrid area of southeastern Missouri and northern Arkansas. It was so vigorous that the Mississippi River appeared to flow backwards, according to eyewitness reports. New Madrid itself was destroyed in the final quake, St. Louis suffered substantial damage, and church bells were said to ring as far away as Boston, Massachussetts and York, Ontario.


For more information, the Missouri Department of Natural Resources has additional information here. There are also multiple books on the history of the quakes, On Shaky Ground: the New Madrid Earthquakes of 1811-12, and The New Madrid Earthquakes among them. It’s a fascinating topic in early American – and in geological – history. Additionally, the city of New Madrid, Missouri has a website to visit as well. Enjoy!