DENVER FALL 2020 MINERAL AND FOSSIL SHOW

 I am no longer a curmudgeon. I am a curmudgeon emeritus.  

                    James Gibbons

Our interesting year continues.  And in my case continues day after day after day as I essentially self-quarantine at home. I am tired of yard work, miss my daily coffee shop meetings with friends, miss camping (Colorado sites are packed), wish for resumption of club and mineral group meetings, and regret my knees will not take bending and walking to collecting sites.  I also greatly regret that science is taking a terrible beating in Washington and in some of the national news media. The future of our nation, and in fact the planet, depends upon “real” research and listening to the advice of scientists.  Our children and grandchildren are going to inherit a planet that will reflect the sins of the current generation.  And, as the beating goes on and on, who will want to become a STEM major in higher education, or who will want to believe the opinion of scientists?  For me, it is a disturbing situation and I regret the lack of a magic wand to correct and make positive changes for humanity.

The easy path of aging is to become a thick-skinned, unbudging curmudgeon, a battle-ax. To grow soft and sweet is the harder way.

                          James Hillman

I keep telling myself to wait, things will get better, stay healthy, and remember the rainbows arrive after the storm.  Well, speaking of rainbows Charlie Chaplin noted that “you'll never find rainbows, if you're looking down.”  So, I decided to look up and what did I spot, the 2020 abbreviated version of the Colorado Mineral and Fossil Fall Show—a rainbow!  Now the question arises of sneaking up to the Show, or being safe and staying home (as my children would prefer). In fact, a second decision involved attending the Fall Show at the Crowne Plaza Hotel (Sept. 11-15) or the Denver Expo Gem Show and the Denver Show, both at the National Western Complex (Sept. 11-21).  Which would it be?  I am still quite spooked about COVID-19 so picked the smaller Show at the Crown Plaza and decided to forego the much larger Denver Western Complex shows with a larger number of people.  It was a good decision.

So off I went for a day’s visit to Denver and an escape from yard work and the ho hum of the self-quarantine.  I had my mask (actually three), hand sanitizer, and the smarts to work with social distancing protocols.  It tuned out to be a great day with limited attendance, lots of big hand sanitizer bottles scattered around, and dealer tables spaced far apart with no jostling of buyers.  In addition, I had several informative visits with dealers only too happy to have customers—I mean listening to Dennis Beals spin yarns about collecting garnets south of the border is classic.

Upon entering the building at a few minutes before opening time I was warming greeted by informative “guides” who pointed out the numerous showrooms available for perusal by the general public.  As usual, I tried to sneak into the wholesale room just to see the specimens but was detained by a nice security person.  Too bad as the tables looked nice. 

The ballrooms were large and tables widely spaced.  Some had sneeze guards installed.  Bottles of hand sanitizers were scattered around the rooms.
 

Murph's Petrified Wood had a nice collection of polished slabs, mostly international in origin.

The centerpiece of Murph's collection, noted in the center in above photo, was a slab from Indonesia. 

A little out of my price range but a beautiful, museum quality, specimen of brochantite (hydrous copper sulfate) crystals from the famous Milpillas Mine in Sonora, Mexico..

Way out of my price range at $20k; however, Kristalle from Laguna Beach, CA, always has beautiful specimens including this brazilianite (hydrous sodium aluminum phosphate) from Brazil.

 

Everyone likes gold, especially specimens shown by Kristalle.

One of my favorite minerals, variscite, the rare hydrated aluminum phosphate collected from Clay Canyon, UT.  Variscite is green while the lighter yellow-like material is probable crandillite (another phosphate).

Dennis Beals from XTAL in Denver always has a nice selection of minerals (very reasonable prices) and yarns.

Blue hemimorphite (hydrated zinc silicate) from the Ojuela Mine, Durango, Mexico. Is this the real color of hemimorphite? 

Few fossils were available but these Moroccan shark's teeth and invertebrates were scattered among selenite crystal lamps, small spheres, a cephalopod bowl, and some other "stuff."  

Utah Tiffany Stone (Trade Name) mined for beryllium at Spoor Mountain in the West Desert of Utah.  These nodules were originally carbonate clasts, then replaced by purple fluorite which was then replaced by opal and/or chalcedony.  Microscopic grains of bertrandite (hydrous beryllium silicate) in the fluorite provide the beryllium available for mining by Brush Wellman.  
 

There was even an Estate Sale offering minerals.

The main emphasis of the sale were specimens of native gold and silver; however, there were other minerals available for purchase.

Outside of the hotel there were a few scattered tents and the Covid-19 protocols were tight.
 

And how could a show not have a display of amethyst cathedrals? 

Albert Einstein said, we act as though comfort and luxury were the chief requirements of life. All that we need to make us happy is something to be enthusiastic about. I would add that a good old-fashioned rock and mineral show makes any ole rockhound happy in the time of Covid.

 

ANAPAITE: NOTHING TO WRITE HOME TO MOMMA ABOUT

 

I was rummaging around in my drawers of minerals attempting to kill some time and trying not to feel sorry for being self-quarantined when I stumbled on an older looking perky box labeled anapaite.  A “long time” ago I had checked on this mineral after purchase and had written “phosphate” on a label. OK, so what was it?  The collecting locality was “Cerdanya, Catalonia Spain.”  That must be a nice place to visit came into my mind so I decided to check it out, not that I will ever make it to Spain.  I only knew a few insignificant “facts” about Catalonia: 1) Catalans are trying to win independence from Spain and speak the Catalan language; 2) Barcelona is the second largest city in Spain and is a major tourist destination on the Mediterranean; 3) Salvador Dali was a Catalan; 4) the northeastern part of Catalonia contains the Eastern Pyrenees, part of the Pyrenees Mountains, running east-west and forming the border between Spain and France—sort of.  The Principality of Andorra, a microstate of ~180 sq. miles, is stuffed in along the border as the official boundary splits to accommodate this tiny area.  As a kid I was a geography freak (still am) and studied intensely every map I could lay my hands on (not many in my small Kansas community).  Places like Andorra I could only imagine in my daydreams but did manage to nab some Andorran stamps with “pretty pictures.”  

Tectonic map of southern Europe, North Africa and the Middle

East, showing tectonic structures of the western Alpine 

Mountain Belt.  The Himalayan Mountain Belt continues to the

east off the map. Map Public Domain credited to Woudloper.

So, as I was learning about the mineral anapaite, I was also learning about the geology of the Pyrenees Mountains—who said I could not multitask?  The current configuration of the Pyrenees Mountains is related to the collision of the Iberian (Spain and Portugal) Plate and the Eurasian Plate in the later Cretaceous and early Tertiary.  The Iberian Plate was subducted by the overriding Eurasian Plate creating numerous faults and compressional structures as the once independent Iberian Plate was being squeezed between Africa and Europe.  In fact, the Pyrenees represent the western edge of the ~8000 miles long Himalayan-Alpine Belt that formed as a result of collisional dynamics between Arabia, India, Asia, and Europe—plates were on the move!

Sketch showing Eurasian Plate overriding Iberian Plate during the early Tertiary.

However, the Pyrenees’ collision dynamics were unlike the tectonic activity in the Himalayan and Alps mountains.   In the latter system, where continental plates with low densities collide, they do not subduct beneath each other, at least not much. But the crust does shorten, as the margins of the two colliding continents together with whatever was between them get scrunched together into huge folds and uplifts.  That collusion describes the Himalayan and Alps mountain zones (Gibson, 2014). However, the Pyrenees were not generated by a continent to continent collision, but merely reflect the confrontation of two distended but continuous continental domains during the Tertiary, leading to the incipient underthrusting of the Iberian crust under the European crust (Canerot, 2016).

Continent to Continent plate collision with crustal shortening causing rising elevation. Public Domain map with credit to U. S. Geological Survey.

In the later Tertiary (Miocene) several structural basins formed (probably due to extensional tectonics and faulting) within, and adjacent to, the Pyrenees including the Cerdanya Basin where several hundred feet of lacustrine (lake) sediment accumulated as organic ooze and diatomite (composed of fossilized diatoms which are microalgae). Within these lake rocks geologists located phosphate minerals, mostly anapaite and fairfieldite, in veins, nodules and spherulite beds.  These phosphatized sedimentary rocks are diagenetic in nature (alteration of existing minerals by chemical change) and very dependent on environmental conditions of deposition and are quite different from phosphate minerals described from marine systems (De las Heras and others, 1989). In marine units, phosphorus accumulation occurs from atmospheric precipitation, dust, glacial runoff, cosmic activity, underground hydrothermal volcanic activity, and deposition of organic material. The primary inflow of dissolved phosphorus is from continental weathering, brought out by rivers to the ocean (Delaney, 1998). 

Location of Cerdanya Basin along axis of Pyrenees Mountain.  Map from Lewis and others, 2000.

Almost all igneous rocks also contain a phosphate mineral and it is almost always an apatite group mineral that forms as an accessory mineral.  Again, the accumulation of igneous phosphatic mineral is much different than marine or lacustrine phosphates. When apatites occur as accessory minerals in igneous rocks they are of macroscopic size and are idiomorphic (identifying crystal form). These are generally fluorapatites which are relatively rich in CI and are characterized by high contents of trace elements. By contrast, apatites formed in surface environments are usually sub-microscopic and are barely visible. These latter apatites are usually carbonate fluorapatite in sediments, or hydroxyapatite in vertebrate skeletons (Lucas and others, 1997).   

Anapaite [Ca₂Fe(PO₄)₂-4H₂O] is an interesting mineral—for a number of reasons: 1) at the type locality in Anapa, Russia (Crimean Peninsula and formally in Ukraine), it is found in the stems of fossil trees and in phosphate bearing, oolitic iron ore; 2) the mineral occurs in two different crystalline forms—bladed/tabular, and spiky; 3) it is commonly found in rosettes, crust-like subparallel aggregates, in geode-like nodules, and fibers.  

Photomicrographs of green to gray-green anapaite in veins of matrix that may be an apatite group mineral. All crystals are sub millimeter in size.

Anapaite is often green in color but ranges to greenish white, gray-green and colorless.  It has a vitreous luster, a white streak, and is somewhat soft at ~3.5 (Mohs), and transparent. It is not a “write home to momma” mineral but is interesting due to its formation in a freshwater lake.

Early 1930s French postage stamp overprinted for use in Andorra.

REFERENCES CITED

Canérot, J., 2016, The Iberian Plate: myth or reality?: Boletín Geológico y Minero, vol. 127, No. 2/3.

Delaney, M.L., 1998, Phosphorus accumulation in marine sediments and oceanic phosphorus cycle: Biogeochemical Cycles, vol.12, no. 4.

De las Heras, X., J.O.Grimalt, J.Albaigés, R.Juliá, and P.Anadon, 1989, Origin and diagenesis of the organic matter in Miocene freshwater lacustrine phosphates (Cerdanya Basin, Eastern Pyrenees): Organic Geochemistry, vol. 14, issue 6.

Gibson, R., 2014, Alpine-Himalayan Orogeny http://historyoftheearthcalendar.blogspot.com

Lewis, C.J., S.J. Verge, and M. Marzo, 2000. High mountains in a zone of extended crust: insights into the Neogene – Quaternary topographic development of northeastern Iberia: Tectonics vol. 19, no. 1.

Lucas J., Prevot-Lucas L. 1997, On the genesis of sedimentary apatite and phosphate-rich sediments, In H. Paquet and N. Clauer: Soils and Sediments, Springer, Berlin, Heidelberg.

TRANSCONTINENTAL RAILROAD, LUCIN, AND UTAH MINYULITE: A RARE PHOSPHATE

 

Photo taken at Promontory Summit on May 10, 1869, at the completion of the Transcontinental Railroad.

Credit Deseret News Archives.  The telegrapher sent the following message: D-O-N-E at 12:47 P.M.

I have always been interested in Utah geology since leaving South Dakota and Kansas in 1967 and heading to the University of Utah for three years of grad school.  Since rambling around the state on “field trips” was an important part of the curriculum, I became enamored with the great variety of rocks, minerals, and fossils “out there” for picking.  And picking and digging I did, but mostly for fossils.  I also found that after leaving the Wasatch Front in any direction the country was pretty wild and sparsely inhabited—perfect for a geologist and nature lover.  Over the years I walked many a mile looking for someone to help extract my vehicle or digging many hours to pile rocks under the wheels in a mud hole.  I learned early to take along plenty of water, lots of food, and extra petrol. But I, and later with my mentored students, saw some fascinating geology and noted the brightness of the stars on clear nights in the desert.

My intense interest in Utah minerals never really started until I took my leave from academe, moved to Colorado Springs, and joined the Colorado Springs Mineralogical Society.  The local mountains brought back sweet memories of hiking in the Wasatch and Uinta Mountains and I started to unpack a few boxes that held Utah “stuff.”  I was surprised at how many Utah minerals I had previously collected and stored away; it was time to sort, curate, collect, purchase, add to the collection, and write.

Darwin didn't walk around the Galapagos and come up with the theory of evolution. He was exploring, collecting, making observations. It wasn't until he got back and went through the samples that he noticed the differences among them and put them in context.        Craig Venter

One of the first specimens I nabbed in my new quest was from a rock/mineral shop in Ogden and was the green gemmy phosphate labeled variscite collected from the “Lucin Locality” in far northwestern Utah. Box Elder County, home of Lucin, is a huge hunk of land stretching from the Wasatch Front at Ogden, north along I-15 to the Idaho state line and west to the Nevada state line.  It also takes in the north half of Great Salt Lake.  The County has 5,745 square miles and outside of the small communities along the interstate is sparsely populated; the county seat Brigham City has a third of the county’s population of 57,000.  Roads are few and far between with UT 30 the only major road. 

Lucin is a well-known term in Utah due to the “Lucin Cutoff.”  The original Transcontinental Railroad ran from Ogden, in the Wasatch Front, west until toward Wendover, Nevada, on the State line but needed to detour north around Great Salt Lake. Old Lucin was a water stop for the railroad and was situated about 10 miles north of its current location.  In 1901 the railroad started construction of a trestle (~12 miles) and a causeway across the Lake and then rerouting the railroad in the general direction of Wendover.  Well, the residents of Old Lucin were about to lose their livelihood so they packed up ”lock, stock, and barrel” and moved south 10 miles to establish a new water stop at New Lucin and hence the Lucin Cutoff was in place.  The Cutoff shaved about 44 miles off the length of the railroad and also eliminated numerous curves needed to cross the Promontory Mountains. By 1959 the Central Pacific Railroad eliminated the need for a trestle and completed a causeway across the entire Lake.

In addition to the railroad, mines in the Lucin District produced, from 1870-1955, about three million dollars (year of value unknown) of low-grade copper and iron from over 6000 mines, pits, badger holes, and other miscellaneous diggings (Blue, 1960).  New Lucin is a deserted and a “Ghost Town” today.

The original route of the Transcontinental Railroad and the Lucin Cutoff.  Map Public Domain with author unknown. 

I have tromped around some of Box Elder County looking for vertebrate fossils in Miocene and Pliocene tuffaceous sediments.  I was not terribly successful but did publish on an interesting Tertiary rodent from the more eastern part of the county.  I also had the opportunity to see, in my field tripping days at the University, the Precambrian rocks in the Grouse Creek Range north of Lucin.  In those days the rocks were generally listed as older Precambrian.  Today they have more specific Archean (older) and Proterozoic (younger) ages assigned and are known as an accreted terrane, about the same age as the Wyoming Craton (>2.5 Ga), or even part of that Craton.

Location of Grouse Creek accreted terrane.  Map Public Domain and credited to: Abenne1 / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

In addition, a couple of my Postings described minerals collected in the Tecoma Hills near Lucin (see Feb. 12, 2019).  However, the best- known mineral collected from Box Elder, County is the green phosphate variscite (but probably metavariscite).  It is similar looking as the variscite collected by Ed Over and Art Montgomery from the Little Green Monster Mine in Clay Canyon, Oquirrh Mountains west of Salt Lake City.  However, those Clay Canyon concretions are more colorful and contain a greater amount of crandallite (another colorful phosphate).

The Lucin phosphates were first collected and mined in the early 1900s by Frank Edison and Edward Bird on their Utahlite Hill Claim.  Since 1910 there have been a variety of rockhounds and claim owners prospecting on the Hill (mainly for variscite).  Today there is a small open pit that was previously mined but Marty and others (1999) stated “the mineral and surface rights originally belonged to the Union Pacific railroad.  Santa Fe Gold/Newmont recently acquired the mineral rights.  The property is presently under lease…”  I don’t know what has happened in the last few years since the Marty paper.

Of the minerals at Utahlite Hill, one of the more rare and most interesting is minyulite, a hydrated potassium aluminum phosphate [KAl₂(PO₄)₂(OH,F)-4H₂O].  The orthorhombic crystals are prismatic, elongated and usually terminated. Most crystals are colorless although some may exhibit shades of pale white, light green, or yellow. Crystals are tiny, usually a millimeter or two, transparent, soft (~3.5 Mohs), and often form radiating spherules or sprays. The luster ranges from vitreous to silky.

 

White sprays and spheres of silky minyulite needle-like crystals. Width of mineral mass ~2.5 mm top photomicrograph; length of middle mineral mass ~2.5 mm; width of bottom mineral mass ~6 mm.  The matrix is probably a druse of carbonate-fluoroapatite.

Marty and others (1999), in their definitive article on the Utahlite minerals, noted that minyulite crystals were limited to one small pocket and that area is now inaccessible. I have no information on the original collector of my specimen except that at one time it was in the collection of Shannon Minerals in Arizona.  Nikischer (2012) described a substantial accumulation of Lucin minyulites originally collected by Ted Morley (Piedmont Minerals). Nikischer purchased the Morely collection (early 1970s) but did not “locate” (in the several tons of mineral flats/boxes) and describe the minyulite until ~2012.  It seems these Morely Lucin specimens “may actually be the finest minyulites ever found!” However, I could not locate Lucin minyulite listed as “for sale” on the current Excalibur, or Shannon Minerals websites, nor in fact, on any dealer website.

Minyulite is a secondary mineral that needed an original phosphate mineral(s) to form.  At Lucin the secondary phosphates formed from hydrothermal solutions percolating through, and dissolving, ions in the Meade Peak Member of the Permian Phosphoria Formation. The phosphatic limestone and chert of the Phosphoria is highly brecciated and allowed fluids heated by nearby igneous intrusions to roam through the rocks and reach cooler temperatures where crystallization of the secondary phosphates occurred.  Minyulite is probably the last secondary phosphate to crystallize.  (Marty and others, 1999).

With my interest in both phosphates and the Black Hills of South Dakota it would be interesting to nab a minyulite specimen from the Ross Hannibal Mine in the Lead District.  I will keep my eyes peeled.

I want to thank Tom Loomis of Dakota Matrix for creating and encouraging my interest in the phosphate minerals of the Black Hills and other localities.

 

REFERENCES CITED

Blue, D.M., 1960, geology and ore deposits of the Lucin Mining District, Box Elder County, Utah, and Elko County, Nevada: M.S. Thesis, University of Utah.  

Marty, J., D. G. Howard, and H. Barwood, 1999, Minerals of the Utahlite Claim, Lucin, Box Elder County, Utah: Utah Geological Survey Miscellaneous Publication 99-6.

Nikischer, T., 2012, An old discovery of superb minyulite: Mineral News, vol. 28, no.4.

LUCIN UTAH