IDOcrase: WHERE HAVE YOU GONE ?

CRYSTAL OF VESUVIANITE FROM MEXICO (DESCRIBED BELOW).  LENGTH~1.4 CM., HEIGHT ~1.2 CM.

Ido, as a male name, is of Germanic or Dutch origin and was more popular in long past years. Today the name, for new born children, is almost non-existent with only three U.S. babies born in 2011 awarded that moniker.  Likewise, it appears the mineral name idocrase has gone by the wayside after being “replaced” by vesuvianite.  Perhaps that is not quite correct as noted below; however, for some reason my mineralogy class had these nice crystals of “idocrase” in the collection, and that is what I learned to identify.  I really did not recognize the name vesuvianite until years later when I examined beautiful faceted specimens in a jewelry shop.  And, it was not until several years later that I connected idocrase and vesuvianite as being different names for the same mineral.

Vesuvianite was actually named “first”, in 1795, by Abraham Gottlob Werner for a mineral found near/at Mt. Vesuvius.  As best I can tell, Professor Werner was working to distinguish grossularite, a garnet, from this “other thing”---vesuvianite—that were found in metamorphosed limestone blocks blown out by the volcano. Werner was not all that healthy in his adult life and did not travel outside of Germany; therefore, some collector brought the specimens from Italy to his lab at Freiberg (I presume at the Freiberg Mining Academy).

Essentially every geology student studied Werner in their historical geology class because of his erroneous theory about Neptunism—that all rocks formed when minerals crystallized in oceans of the primitive Earth.  However, he did redefine the term "geological formation" to mean rocks deposited/crystallized at the same time.  Previously “formation” was used to define the chemical makeup of a rock.  On the other hand, he tried to establish “universal formations” to indicate that certain rock layers were deposited at the same time all across the surface of the Earth.  But, the 1700’s were a different time and a different place and geology has advanced!

Students of geology also know Werner as the “Father of Mineralogy”. Werner was a classical descriptive mineralogist and in 1774 published Von den äusserlichen Kennzeichen der Fossilien.  The book offered a classification of minerals along with techniques for identification.  Wernerite is a variety of scapolite, an intermediate member of the marialite (Na₄Al₃Si₉O₂₄Cl)---meionite Ca₄Al₆Si₆O₂₄CO₃ solid solution series (www.mindat.org).

Rene Just Haüy is known, as least by some scientists, as the “Father of Modern Crystallography” and is the author of Essai d'une Théorie sur la Structure des Cristaux (1794), and five volumes of the Traité de Mineralogy (1801).  His ideas about crystals and crystallography came about in a serendipitous moment.  He dropped a piece of calcareous spar (calcite) and it broke into many “little” rhombs.  Voila, the small broken pieces looked just like “mom and dad”--same cleavage faces and same face angles.  Haüy had a personal collection in excess of 12,000 specimens but nearly died in the French Revolution (as an ordained Catholic priest he did not want to swear allegiance to the Revolution).  He taught at the Sorbonne and the Muséum d'Histoire Naturelle but was fired from those jobs by members of the Bourbon Restoration Government. It was a really tough time to live in France, but he did retain his “head” and died more peacefully in 1822.

Haüyne is a feldspathoid, sodalite group (often a beautiful blue color), [(CaNaCa)_4-8(Al₆Si₆(OS)₂₄)(SO₄Cl)_1-2] named after this mineralogist (www.mindat.org). At any rate, in about 1799, Haüy decided the mineral named vesuvianite by Werner should be named idocrase!  Why, I have not been able to determine.  I don’t know if the naming was due to a lack of communication among the few mineralogists of the world, or maybe Haüy just liked the name better!  Whatever the case, there has been some minor confusion about this mineral for a couple of centuries.  It is my understanding that gemologists prefer idocrase while crystal collectors like vesuvianite.  However, the names seem to be used interchangeably in the popular literature, BUT Mineral Data (www.rruff.geo.arizona.edu), the International Mineralogical Association, and MinDat (www.mindat.org) use vesuvianite as the “official” mineral name with idocrase listed as a synonym.  I don’t have the slightest idea why my mineralogy class preferred idocrase except that this offering was a long time ago!  So, from now on, for me, it is vesuvianite!

Vesuvianite has a very complex, at least for me to understand, chemical formula and interestingly contains both neosilicate (SiO₄ with a silicon anion and one tetrahedron) and sorosilicate (Si₂O₇ with two tetrahedra) groups:  Ca₁₀(Mg, Fe)₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)_4.   The nicest specimens (and I have not seen many) that I have observed are green in color but specimens also might be brown to yellow to even a nice blue-purple in color.  If in crystals, they are usually prismatic and “eight-sided” with one set (of sides) being quite dominant so the prisms look square in cross section.  They are commonly terminated with a four-sided pyramid.  Vesuvianite is a fairly hard mineral at ~6.5 (Moh’s) with a vitreous to “greasy” luster.  Gemmy vesuvianite is transparent to translucent while other specimens are less than translucent (not quite opaque but something).

GEMMY AND FACETED VESUVINIATE, 1.25 CT, 8 x 6 CM.  PHOTO FROM EBAY.



Other than Mt. Vesuvius in Italy, vesuvianite, including gemmy varieties, is found in a number of localities world-wide.  Cyprine is a sky-blue vesuvianite (copper impurities) first reported from Norway but now known from other locations.  Californite is a compact (non-crystalline) and massive type of vesuvianite often cabbed and sold as California Jade.  The Jeffrey Mine in Asbestos, Quebec, produces a very rare violet to magenta variety (manganese impurities).  Egeran is browner in color and reported from the Czech Republic.   



   

TOP CRYSTAL: DOUBLE TERMINATED BICOLOR MANGANOAN VESUVINIATE CRYSTAL.  SIZE: 1.5 X 1.0 X 1.0 CM.  PHOTO FROM EBAY.

Most vesuvianite occurs in skarn deposits, especially in contact metamorphism of limestones.  However, at times it is found in regionally metamorphosed schist and serpentine.   I have never observed vesuvianite in the field (I was always looking for fossils) but Eckel and others (1997) have documented several localities in Colorado.  Perhaps the most interesting statement: “Park County—Badger Flats District.  Grayish green vesuvianite is an abundant constituent of calc-silicate gneisses of the Tarryall Springs District”. Maybe a field trip is in order!

The lone specimen that I have in my collection is a nice, but non-gemmy, crystal from “Lake Jaco, Mexico”.  However www.mindat.org noted that the locality named Lake Jaco is really a misnomer since the early mineralogist collecting crystals did not want competition at the mine!  So, as best I can tell the locality is Sierra de la Cruz (Lake Jaco), Mun. de Sierra Mojada, Coahuila, Mexico.  At least that is how MinDat lists the name.

In three words I can sum up everything I’ve learned about life: it goes on.  Robert Frost

REFERENCES CITED

Eckel, E. B. (and others), 1997, Minerals of Colorado: Fulcrum Publishing, Golden.

Post Script:  I recently acquired two green, gemmy crystals collected several years ago from the VAG Mine, part of the Belvidere Mountain Quarries. The quarries produced chrysotile asbestos from the early 1800's until 1993.

LENGTH ~1.2 CM.

   

LENGTH ~ 2 CM.

BLUE-PURPLE HALITE

HALITE FROM DELAWARE BASIN, NEW MEXICO. CUBE ~2.5 X 2.5 CM

I have always associated the mineral halite (NaCl) with white-colored table salt, the shimmering small crystals on the “Bonneville Salt Flats” in western Utah, the salt anticlines and salt valleys in the Paradox Basin of the Four Corners, and the massive subsurface deposits left behind by the evaporating Permian cratonic seas.  These thick subsurface beds of Permian age are abundant in my native Kansas and, in my youth, could be observed by descending into one of the mines and picking up a few crystals.  Although mines at Hutchinson and Kanopolis are still producing “rock salt” for a variety of uses, getting a free visitor trip into the diggings is virtually impossible. 

HALITE CRYSTAL FROM PERMIAN SALT, KANSAS. CUBE ~ 2.5 X 3.0. 

But even if you cannot descend into a mine there are numerous opportunities to observe natural halite on the surface--the above mentioned Bonneville Salt Flats, for example, and certainly the vast Searles Lake region in California where nice pink crystals are exposed over an area of about 20 mi².

HALITE CRYSTALS FROM SEARLES LAKE, CALIFORNIA.  WIDTH ~9 CM.

We all realize that halite easily dissolves in ordinary water, H₂O.  This process is “good” in some cases, for example in flavoring our foods.  But in other instances, the results are badly degrading the environment---“road salt” runoff certainly contaminates local streams and in some cases even ground water.  The solubility of halite is also responsible for the large number of sinkholes in western Kansas (and many other states).  Although Kansas is not known as a “cave state” where carbonate rocks dissolve to form voids, many people are surprised about the subsurface solution of Permian-age halite and gypsum with resulting collapse of overlying rock layers. A couple of examples include the Ashland Basin in southwestern Kansas, perhaps 10-12 miles long, and representing a series of coalescing sinkholes.  The Basin lies in the High Plains Physiographic Region and that upland is perhaps 400-500 higher than the bottom of the sinkhole.  In Clark County, also in southwestern Kansas, the circular Big Basin is a collapse structure about one mile in diameter and dissected and drained by the Cimarron River.

GOOGLE MAP VIEW OF BIG BASIN, A SINKHOLE LOCATED IN SOUTHWESTERN KANSAS.  THE CIRCULAR STRUCTURE IS ABOUT ONE MILE IN DIAMETER.  NOTE ROAD DISSECTING THE FEATURE.

In central Kansas, where I spent my youth wandering hills of the Dakota Formation (Cretaceous), I was fascinated with the amount of halite leaching out of the rocks.  The Jamestown Wildlife Refuge is a major stop for migrating waterfowl in the Central Flyway, and a tremendous place to “bird watch”.  The refuge is a large marsh with a series of salt water springs and seeps issuing from the upper part of the Dakota.  As the water evaporates halite crystals are constantly being produced (and re-dissolved) along water’s edge.

I grew up on the Saline River below its contact with the Dakota and the water was highly charged with sodium chloride and could not be used for direct irrigation of plants and crops (several thousand milligrams of chloride per liter).  The Saline is a fairly long river at ~400 miles (entirely in Kansas) but is actually quite small in size---except during the numerous floods!  There are at least two “Salt Creeks” flowing into the Saline and French explorers noted the “briny” water as early as 1724.

So halite, a somewhat interesting mineral, is similar to many of the other evaporates--they seem rather dull as a collectable mineral. Halite comes in a variety of colors, mostly light in nature, with the tint commonly due to small amounts of impurities.  However, at a recent show my eyes about popped out when I discovered a dealer with several specimens of blue to purple halite, a really bright-colored halite! At first I thought perhaps this was simply a crystal constructed from a halite-saturated solution with food coloring added in.  But, I was assured the crystal was natural.  I had really never seen blue to purple halite before but thought it would look nice in my collection for a couple of dollars.  After returning home I begin a literature search to try and locate information about this halite and came across several specimens listed for sale in the 50 to 500 dollar range.  That aspect made me feel good about my frugal purchase!  

There are some rather famous collecting localities for colored halite in Poland; however, it appears that all blue to purple halite collected in this country comes from potash mines in the Delaware Basin of southeastern New Mexico: the upper Permian McNutt member of the Salado Formation Bickham, (2012).  As for origin of the blue to purple color, many/most geologists believe the coloration is due to gamma-ray bombardment of halite with the rays coming from radioactive potassium-40 found in associated minerals (like sylvite: KCl and isomorphous with halite).  K-40 is rare but does occur in some instances.  The gamma rays then disrupt the lattice structure of the halite and force the displaced electrons to reflect the blue to purple wavelengths from the visible light.  I am not enough of a mineralogist to vote yay or nay on this thought but it sounds good to me.  Bickham (2012) has some other ideas that seem worth exploring.  Whatever the reason for the bright color, these specimens make very nice displays and certainly generate many questions from visitors.

REFERENCES CITED

Bickham, M., 201, Chemical Analysis of Blue Halite [abs]: Geological Society of America Abstracts with Programs. V. 44, no. 1.

SPINEL: THE FORGOTTEN GEMSTONE



THE BLACK PRINCE'S RUBY DISPLAYED ON THE FRONT OF THE IMPERIAL STATE CROWN OF GREAT BRITAIN.  PHOTO PUBLIC DOMAIN FROM THE CROWN JEWELS OF ENGLAND.

I attended a recent show and one of the vendors had a very nice selection of faceted, gemmy spinels.  In fact, several displayed spectacular cuts.  I was further impressed by the specimens when I learned they were natural spinels rather than laboratory-produced crystals.  But, I really had to rattle the back part of my mind to even recall something about the mineral!  I actually had not thought much about spinel for years.

I don’t remember much about spinel from my undergraduate mineralogy class except seeing some very hard octahedral crystals rolling about in a white specimen box.  At first glance it was easy for me to get the crystals mixed up with magnetite octahedrons and I sort of wondered if there was a relationship.  But then, something in my brain said “wake up Mike, use a magnet” to weed out the spinel.  I never used the magnet since I don’t recalling needing to identify spinel on any test!  In fact, I don’t believe that I ever observed or identified the mineral in the field.

Later in life essentially the only thing I knew about spinel was that for years the royal British jewelers were a bit confused about gems in the crown jewels!  The Black Prince’s Ruby and the Timur Ruby (~350 carats), part of the crown jewels, are actually red spinels; however, before modern gemological tests were readily available most red–colored gems were termed rubies.  The Black Prince’s Ruby is ~170 carats in weight but is more of a cab or blob and is not faceted.  It prominently sits on the front of the Imperial State Crown, which in turn may be seen by visitors in the Tower of London Jewel House.  The Samarian Spinel is part of the Iranian Crown Jewels and may be the largest spinel gem in the world (~500 carets).  Legend has it this particular spinel adorned the biblical Golden Calf, constructed by the Israelites (for worship) while spiritual leader Moses was receiving the Ten Commandants.

A recent advertisement came across my computer screen extolling the thought that black spinels were a wonderful substitute for more expensive “black diamonds”.  That blurb intrigued me even more so I begin to dig through the literature, and also remembered that somewhere in the recesses of my collection was a specimen of spinel.  

 

Spinel, a magnesium aluminum oxide (MgAl₂O₄), comes in a variety of natural colors with nice stones being colorless (rare), red to pink (probably due to trace chromium), orange to purple (probably due to trace iron and chromium), black (probably due to trace iron), and blue (probably due to trace iron and cobalt).  A jeweler told me that very few faceted spinel gemstones are enhanced; occasionally, some are heated to improve the color. As noted above, red spinel is often confused with ruby, a red aluminum oxide (Al₂O₃) with trace chromium supplying the color in both.  In fact, they often occur together with ruby forming after the available magnesium is “used up”.

GEM RED SPINEL FROM THE GEM AND MINERAL COLLECTION OF THE SMITHSONIAN'S NATIONAL MUSEUM OF NATURAL HISTORY. PHOTO COURTESY OF DANE A. PENLAND.

 

Spinel is a hard mineral coming in at 7.5-8 on the Mohs’ scale and forms in the isometric system; most crystals are octahedrons.   It is translucent to transparent to even opaque and has a vitreous luster.  It does not cleave. As I understand it, most gem spinels are found in alluvial gravels with the finest red, pink and orange specimens coming from Myanmar (Burma).  Sri Lanka (Ceylon) is a major producer of blue and violet stones; however, it appears that new deposits have been located in Tanzania.

One of the unfortunate facts (or depending upon your point of view, fortunate) is that spinel is easily synthesized and colored and many people simply do not appreciate the beauty of natural spinel; they may not even realize that “natural” spinel exists!  In fact, some of the colors in synthetic stones do not appear in nature and virtually all clear crystals marketed as spinel are synthetic.  Synthetic spinel also is often used to replicate other gemstones such as diamond, ruby and sapphire---know your dealer! Have an old high school class ring with a big colored stone?  There is a good chance the colored stone is synthetic spinel.

Spinel is a member of the “Spinel Group” of minerals crystallizing in the isometric system and with a general formula of AE₂O₄.  A represents various metallic cations.  Minerals in this group include the Spinel or Aluminum Series where E is Aluminum, the Magnetite or Iron Series where E is iron (Fe), and the Chromite or Chromium  Series where E is chromium._.  The Aluminum Series includes the gem spinels, but at times the magnesium of spinel (the A) may be replaced by zinc (the mineral gahnite), iron (the mineral hercynite), or manganese (the mineral galaxite).  The best known mineral of the Iron Series is magnetite (Fe₃O₄) while chromite (FeCr₂O₄) is a representative of the Chromium Series.

MAGNETITE OCTAHEDRONS FROM MAGNET COVE, ARKANSAS. WIDTH OF SIGLE CRYSTAL ON RIGHT ~1 CM.

Spinel is found in both igneous rocks (basalts, peridotites, kimberlites) and high temperature contact metamorphic rocks (especially hornfels and marbles).  Some of the most beautiful specimens that I have seen in museums are where a crystal of red spinel is perched on a metamorphic white marble.

The specimen in my collection (black and opaque probably due to iron) was purchased at a show and labeled “Huntington Lake, Fresno County, Calif.”  As best that I can tell this spinel occurs in “a deposit of pre-Cretaceous crystalline limestone changed to marble and containing several smaller bodies of calc-silicate hornfels… It is in the high Sierra Nevada, 3 miles north of the east end of Huntington Lake, at an elevation of 8500 to 8800 feet. As mapped, this limestone pendant is over 10,000 feet long and from 1250 and 3000 feet wide… the contact-metamorphic rocks formed where the Sierra Nevada batholith intruded a region deeply covered by older sediments, of which the original upper portions have been removed by erosion, including glaciation” (Logan, 1947).  Pink, green and lavender crystals also have been collected from this locality.

SMALL MASS OF BLACK SPINEL OCTAHEDRONS COLLECTED FRESNO COUNTY CALIFORNAI.  WIDTH OF SPECIMEN ~5.2 CM.  LARGE CRYSTAL UPPER RIGHT IS BELOW.

 

ONE HALF OF A SPINEL OCTAHEDRON FROM CALIFORNIA.

I certainly have not collected crystalline spinel (Spinel Series) anywhere in Colorado and Eckel (1997) stated that “spinel…has seldom been observed in Colorado”.  However, he also noted that Spinel Series minerals “are common accessory constituents of mafic igneous and metamorphic rocks… and are much more widespread than indicated by the literature.  Much of the spinel…occurs associated with Precambrian massive sulfide deposits”.
Gahnite, the zinc-dominant member of the Spinel Series, “is commonly found in Colorado in Precambrian metamorphosed, base-metal sulfide deposits and in a few pegmatites of granitic composition…It is moderately common in such deposits in the Front Park, and Sawatch Ranges”.  One of the local rock and mineral shops has several specimens of gahnite on display and for sale; however, the mineral is non-crystalline and is a granular (small) blackish (maybe dark, dark green), smear on country rock.  I certainly would not be able to identify it as gahnite without its label, or perhaps by using a microprobe stuck in my back pocket.

Several gem dealers refer to spinel as the “forgotten gemstone”.  It certainly was an import gem at one time---witness the crown jewels.  However, with the advent of synthetic spinel the stone seemed to decrease in value.  My suggestion is that readers ask their dealers for a peek at the real thing---you will be surprised at the gem’s beauty.

Rich and rare were the gems she wore,

And a bright gold ring on her hand she bore.

Thomas Moore

 

REFERENCES CITED

 

Eckel, E. B. (and others), 1997, Minerals of Colorado: Fulcrum Publishing, Golden, Colorado.

 

Logan, C. A., 1947, Limestone in California: California Journal of Mines and Geology, v. 43, no.3.

GREEN RIVER: GATES OF LADORE

The Whoa Moment.  A time where you want to yell WHOA, back it up and let me see that again.  A moment when you get a rush, feel goose bumps, a moment that you would like to preserve “forever”.    How many of those moments have rock hounds experienced in their lives?  The first time you faceted a piece of glass and it came out looking like a Tiffany jewel?  Whoa, let me savor that moment again.  What about the first time that you viewed Longs Peak from “up close”—a rush of adrenalin?  One of the great joys of my life is coming around the corner and, Whoa, there it is, play it slowly.  The first time that one of my students found a really nice shark’s tooth on a field trip—a Whoa Moment to a teacher as the student’s eyes lit up and all of a sudden they “understood” what it was all about.  A Whoa Moment is a serendipitous moment, something completely unexpected, but pleasant, happens when you least expect it.  I was in Portland, Oregon, a few years ago and the clouds parted and there was Mt. Hood—completely unexpected.  In about five minutes it was gone. Play that again--please!  It didn’t.  So, this is what makes life interesting for me (and probably you)—what is coming around the corner?  When will the next Whoa Moment arrive?  That certainly is one of the reasons that I am a rock hound and have retained my interest in geology through the decades.  There is always a chance for a Whoa Moment.

Colorado is fortunate to have, in its geography/geology, a thousand places where one could experience a Whoa Moment; maybe even ten thousand or more.  One of those places is the Gates of Lodore in far northwest Colorado, actually a part of Dinosaur National Monument (DNM).  Probably very few of the readers have visited this locality since it is far off the beaten path--- northwest of Maybell (west of Craig on U. S. 40) on CO 318.  However, it is well worth the trip if you are in the vicinity.

LADORE CANYON ca. 1871, SECOND POWELL EXPEDITION.  PHOTO FROM USGS.

 Most visitors to DNM are there because of, well, the dinosaurs.  However, there is much more to the Monument (211,000 acres) than fossils but most people are in a hurry and tend to ignore the back country.  I am often reminded of the movie Vacation where Chevy Chase stands looking at the Grand Canyon for about 30 seconds and then states “let’s go”!  Most visitors to DNM are just passing through the area and therefore miss out on half of the fun.  Let’s go.

The back country of DNM is dominated by canyons of two rivers—the Yampa coming in from Colorado and the mighty Green flowing south from Wyoming.  Both have cut spectacular canyons and both are accessible to the traveler via private or personal river running (permits required), or back country hiking.  Although the scenery in both canyons is almost beyond words, and I was spellbound during my first float with a Whoa Moment that almost took my breath away—the Gates of Lodore where the Green plunges into, and through, the Uinta Mountains.

Any story about the Gates of Lodore would be incomplete without entering into a conversation about John Wesley Powell and his river expeditions of 1869 and 1871 down the Green and Colorado Rivers and finally through the Grand Canyon.  These trips, although not the first through the canyons of the Uinta Mountains, were the first scientific explorations of the Green River.  Powell’s account of the trips was published in 1875 as Report on the Exploration of the Colorado River of the West and Its Tributaries and then reprinted and republished in 1895 as The Exploration of the Colorado River and Its Canyons, and in several later editions. 

JOHN WESLEY POWELL'S BOAT, THE EMMA DEAN ca. 1871, SECOND POWELL EXPEDITION.  NOTE POWELL'S CAPTAINS CHAIR.  PHOTO FROM USGS.

 The Gates of Lodore exposes the red quartzites, shales and sandstone of the late Precambrian Uinta Mountain Group (~740 Ma to ~850 Ma). The walls are steep, the canyon narrow, and visitors must look down from above or ride the rapids down below.  Either way, a Whoa moment is at hand, 

How does the Water
Come down at Lodore?"
My little boy ask'd me
Thus, once on a time;
And moreover he task'd me
To tell him in rhyme.

From the Cataract of Lodore by Robert Southey.

BADGERS, STONEHENGE, AND A FURSTY FERRET

THE EUROPEAN BADGER, MELES MELES.  PHOTO COURTESY OF BBC.

 The big news from Maidenhead, UK, (see previous post) centers around badgers.  Yes, those ornery furry members (Meles meles) of the weasel family.  It appears that a substantial number of people believe the boogers need culling (a nice word for killing).  Another substantial number of citizens love the critters.  A fight is brewing!

I learned that UK cattle have a serious problem with bovine tuberculosis—to the tune of tens of thousands of cattle being slaughtered at a large monetary cost to the farmers.  As with many personal financial losses, there is a tendency to fix the blame on an external force rather looking to an internal cause.  Bovine TB is a nasty disease and in most other countries farmers slaughter an entire heard to prevent its spread.  However, in the UK farmers tend to slaughter only a single infected animal.  That leads us to badgers!  It seems that cattle can infect badgers and vice versa with the disease.  So, the obvious answer to many people is, wait for it, shoot most of the badgers.  But the badgers are quite prolific breeders this year and have vastly increased in numbers.  And those of us who have lived in the Midwest know that unlimited shooting of deer in areas of chronic wasting disease was about as successful as a lead balloon.  So, the argument goes on and on—to shoot or not to shoot.   The problem has reached the highest level of the government and Prime Minister Cameron has now postponed the culling—kicked the can down the road.

In my previous post I lamented about the lack of outcrops in the Thames River basin near Maidenhead.  Perhaps I just missed the rocks, or they were obscured by the vegetation, or maybe modern construction activities destroyed the evidence.  At any rate, I needed my fix of rocks and so begin hunting for areas external of the town.  Well, we located some fascinating rocks; however, they were exotic to the area and not arranged in stratigraphic order!  On the other hand, these rocks were located at a World Heritage Area the world knows as Stonehenge. 

THE STONE STRUCTURES AT STONEHENGE.

We decided to brave the traffic and head west from Maidenhead driving “on the wrong side of the road” for about 70 miles to near the village of Amesbury.  Other than some white knuckle stress the trip was completed without incident.  I do feel fortunate that this excursion was completed midweek in October rather than in prime summer visitor season.

Millions of people around the world have at least heard of Stonehenge, mostly due to these very large rocks laid out in a mysterious arrangement.  There is some sort of stone alignment with the sun and the Summer and Winter Solstices are special times.  However, we (modern populations) often fail to understand that some members of past civilizations were “very intelligent” and were able to interpret and predict celestial events with great accuracy.  These events were marked in a variety of ways including rock windows, stone markers, displays on rock faces, etc.  At Stonehenge the builders marked these celestial events by importing some really large rocks, some as large as 25 tons, and arranged them in a methodical order to maximize astronomical observations and mysticisms. 

A PLACE OF REVERENCE AND MYSTICISM.

The more I tried to learn about the history of Stonehenge, the more confused I became!  However, that seems normal as scientists have been unable to unravel but a small part of the history.  Media outlets have popularized the pagan ceremonies of the modern neo-Druids at Stonehenge, and equated these activities with ancient Druids.  In doing so, they have piqued the interest of the public.  However, the British Museum believes neo-Druids have no connection with ancient Druids, a group of priests living in the UK and France before the arrival of the Romans. And, Stonehenge was long constructed before the ancient Druids obtained any sort of power in the population.

The history of Stonehenge is complex and certainly beyond the scope of this posting. So, I encourage readers to locate some of the hundreds/thousands of articles and books written on the subject—just carefully scrutinize the sources and stick to reputable authors such as the British Museum and academic geologists, historians, and archaeologists. 

Stonehenge, at least what remains, is a circular placement of large exotic rocks arranged within a series of ditches and earthworks.  Although unique in several ways, it is far from being the only example of ancient works.  There are literally hundreds of Neolithic (~4000-2500 BC) and Bronze Age (~2500-800 BC) rock works, rock monuments, and burial mounds located in the UK.  The earliest evidence of human activity at Stonehenge dates to perhaps ~7500-8000 BC and is in the form of holes that held posts (that would be postholes!).  What these poles held up seems to be anyone’s guess. The earliest rock construction seems to be ~3100 BC and involved digging a ditch, and piling up the rocks, in the poorly exposed chalk bedrock (Cretaceous Seaford Chalk).

PERHAPS THIS WAS STONEHENGE?  SKETCH FROM MANDALASROK.COMUF.COMJ.

By around ~2600 BC the builders were using an igneous rock (Ordovician dolerite/diabase) locally called bluestone, and lesser amounts of rhyolite and tuff.  The original source of the bluestone was from Wales, and scientists have long debated the mechanisms of transporting large (several tons) rocks over 150 miles.  Recently workers from the British Museum have suggested the bluestones were actually taken from local glacial erratics—still from Wales but transported to a closer location by Pleistocene glaciers.  

A major building phase from ~2600-2400 BC produced perhaps the most impressive part of the Stonehenge structure—construction of a ring of 30 standing rocks (each 13 feet high, 7 feet wide, 25 tons) capped with 39 “lintel” rocks (10 feet by 3.5 feet)—the so called Sarsen Stones!  These rocks, a silicified Tertiary sandstone, came from quarries perhaps 25 miles distant, or from local glacial erratics.  Inside this circle is a U-shaped arrangement of five “trilithons” (two standing rocks topped by a lintel) held together by a mortise and tenon joint system.  Inside of this arrangement are other rocks including the “alter stone”.

HOW DOES ONE MOVE MULTI-TON LINTEL STONES TO REST ON THE UPRIGHT STONES?

Additional building, and rock rearrangement, of Stonehenge continued for several hundred years, and modern civilizations have contributed to its demise by “taking away” bits and pieces and even whole rocks.  Today Stonehenge is owned by the Crown and surrounding land is protected by a trust.

THE HEELSTONE, COMPOSED OF SILICIFIED TERTIARY SANDSTONE, IS NOT LOCATED WITHIN THE STONEHENGE CIRCLE.

Theories abound as to the use of Stonehenge—take your pick.  Was it a cemetery? Yes, at least part of the time.  A place of mystical or spiritual worship?  Probably.  A place for astronomical observations?  Yes, at least part of the time.  A place for healing?  Maybe, that is a recent proposal. Whatever its use, the builders and users left behind no written record and Stonehenge’s place in history may always be debated.  However, we found it to be a place of marvel and reverence. 

A COOL FURSTY FERRET AFTER A WHITE KNUCKLE DRIVE.

Upon returning to Maidenhead I poured myself a pint of Fursty Ferret and tried to interpret what I had seen—it was confusing!   However, I could picture in my mind a group of ancient people gathering at Stonehenge trying to decipher the events of a Summer Solstice.  

ADDENDUM SEPTEMBER 27, 2013 FROM THE BBC:

A badger cull is under way in England despite protests, the National Farmers' Union has confirmed.

About 5,000 badgers are expected to be killed in controlled shootings over six weeks in Somerset and Gloucestershire.
Supporters say the cull is necessary to tackle bovine TB, which can be spread from infected badgers, but opponents say it is inhumane and ineffective.