FLUORAPATITE, BERTRANITE AND MUHAMMAD ALI

I know little about the geology of Maine and in past excursions was more interested in the fantastic opportunities to sample seafood and explore the home store of L.L. Bean.  Early in my career I spent a week camping along the shoreline while pulling a large pop-up camper trailer.  Sure, I pounded on the rocks but also spent more time stopping on the roadside so we could gorge ourselves on wild berries and hitting the fishing docks in late afternoon to purchase lobsters and mussels right off the boats.  Wow, what a treat.  I also took a very early morning hike to the top of Cadillac Mountain on Mt. Desert Island to see the sunrise since that spot receives the first sunshine of the day in the lower 48.

Later, when I was on the undergraduate research speaking circuit, I presented at Bates College, a beautiful private liberal arts college in Lewiston, Maine.  A “field trip” one evening took the group over to the L.L. Bean home store in Freeport.  In those “olden days” most of us were not living close to a Bean outlet so the home store was just like Christmas.

Lewiston is also well known for a singular event that took place on May 25^th, 1965, when Muhammad Ali knocked out Sonny Liston in the first round of a Heavyweight Championship fight.  After the fight, the 23-year-old Ali called the punch that dropped Liston his secret: "It was a phantom punch. It was lightning and thunder — fast as lightning and booming as thunder from the heavens,"


Now that I have more time I am trying to learn, something in detail, about the geology of New England.  When I taught Stratigraphy, I told my students that we were lucky to live in the Plains’ states since you could actually see rock outcrops.  In New England, the rocks are all covered by vegetation!


The other day I was thumbing through a copy of the Nov/Dec volume of Rocks and Minerals looking for an article containing information on the gem zoisite variety known as tanzanite.  After reading about that gem I stumbled on an article entitled The Emmons Pegmatite: Greenwood, Oxford County, Maine. Something popped up in my mind that said, “you have a specimen from there.”  So, I took a peek in the drawer and there was a small plastic cube box with a specimen collected by David Shannon in August of 1997 or 1999 (ink smeared).


The Emmons Pegmatite was well described by Falster and others (2019) and I urge readers to examine that issue of Rocks and Minerals where I retrieved the following information.


The Emmons Quarry is found on Uncle Tom Mountain in Oxford County, Maine, and was first mined for feldspar in the 1930s; however, that venture was short-lived.  Mineral enthusiasts then started extracting beryl and collected about 5000 carats of gem morganite (pink beryl). Specimen collecting has continued to the present and is especially active with the move of Alexander Falster and William Simmons (and their laboratory) from New Orleans to the Maine Mineral and Gem Museum in Bethel. The Emmons is known for its many phosphate minerals and is Maine’s most species rich pegmatite (109 valid minerals according to MinDat).


The Emmons is part of the New England Appalachian Mountains and the entire New England area has a complex history.  I always had a great deal of respect for the geologists deciphering the history of these rocks, especially with the aforementioned vegetation!  I have lived through an exciting time in the history of geology where “continental drift, eugeosynclines and miogeosynclines were strange bedfellows in my 1960s era Historical Geology class. Today, 60 years later, the entire concept of plate tectonics has evolved into academic dogma.  In my class the text “talked” about Paleozoic mountain building events in the eastern U.S. (todays geography); however, these tectonic pulses, named Taconic (Ordovician), Acadian (Devonian), and Alleghenian (Permian), were distinct events and no one really understood their “cause” or relationship  We just studied uplifts and erosion.  Today we know that shifting plates were colliding with one another, some were subducted with resulting volcanism and intrusions and metamorphism, and microcontinents were often caught in the middle and were accreted to larger continents. All of this action was continuous during the Paleozoic resulting in the supercontinent termed Pangea. Rocks of the Emmons Pegmatite were originally marine sediments deposited in a deep-water marine basin during the Ordovician-early Devonian and were later subjected to deformation and metamorphism during Devonian to Permian tectonism.  For a discussion on the breakup of the supercontinent see Posting October 21, 2019.


My thumbnail specimen that I pulled from the back of the drawer is amazingly rich with albite and other feldspars, manganese dendrites, quartz, several unknowns, bertrandite [Be₄(Si₂O₇)(OH)₂], and fluorapatite [Ca₅(PO₄)₃F]—and probably others.  I purchased it for the nice purple crystals of fluorapatite and the gemmy clear bertrandite for which the quarry is famous. At the Emmons Quarry Falster and others (2019) noted that both bertrandite and fluorapatite result from the corrosion and alteration of beryl and form in the vacated cavities/vugs. 

Purple fluorapatite (F) and clear gemmy bertrandite (B). Width photo ~7 mm.

Note the tiny, submillimeter, tan prismatic crystals marked with a ?, along with fluorapatite and bertrandite.

I presume the lower arrow points to a number of lilac to clear crystals of fluorapatite (submillimeter).  The upper arrow points to a similar situation of stacked crystal of a tan-orange color.  Some of the black mineral may be manganese oxide. Lots of questions!

More questions!

The scientist is not a person who gives the right answers, he's one who asks the right questions.  Claude Levi-Strauss 

I presume the large clear crystal is fluorapatite due to the striations

A nice mixture in a vug.

In Maine we have a saying that there's no point in speaking unless you can improve on silence.        Edmund Muskie

REFERENCES CITED

Falster, A. U., Simmons, W. B., Webber, K. L., Dallaire, D. A., Nizamoff, J. W., & Sprague, R. A., 2019., The Emmons Pegmatite, Greenwood, Oxford County Maine: Rocks & Minerals, v. 94, no.6).

TO THE ARCHIVES: LAZARD CAHN LABELS

I love that microscope!  Lazard Cahn, ~1930.  Photo © courtesy of the Digital Collections at the Pikes Peak Library District.

Since moving to Colorado Springs in 2006 I have tried to remain active in the Colorado Springs Mineralogical Society (CSMS).  The Society can trace its origin to November 1936 when 13 individuals (including two females) met for the purpose of organizing a local mineralogical society.  Lazard Cahn was elected as the Permanent Honorary President; hence, the designation of such on all CSMS publications continues into the 21^st century.  I note with interest that at the initial meeting the new members spent their time examining micromounts under binocular microscopes.  Evidently the new society was the outgrowth of interest by persons studying microscopic crystals under the instruction of Mr. Cahn (twice per week at his office).  The Society was active early on and by 1939 mineral displays were exhibited in Colorado Springs through the Chamber of Commerce.  Today CSMS sponsors a summer rock, mineral and fossil show (except 2020 the pandemic year), monthly meetings, field trips and a variety of other activities.  Check out www.csms.1936.

Since Lazard Cahn is such a revered mineralogist, CSMS members enjoy locating minerals that were, at one time, in his collection, and the mineral labels that accompanied the minerals.  The big jackpot is having an original label, and the specimen.  I have about a half dozen of these jackpots and the posts are in this Blog.

I also was able to acquire several orphan labels that lack the specimens, but then needed to answer the question—how do I preserve these elements of mineral history?  Well, there is a perfect place for these labels, The Mineralogical Record.  The Mineralogical Record magazine is their best known product; however, they offer databases, bibliographies, and a host of other information products including “the Mineralogical Record Label Archive, a collection of original, printed mineral specimen labels representing mineral collections from all countries during the last two centuries. With the possible exception of some of the great museums, it is the largest such collection in the world, with over 15,000 examples cataloged, and another 15,000 to 20,000 duplicates and uncataloged examples.”  See their web site at www.mineralogicalrecord.com. 

So, I am sending 20 Cahn labels to the Archives in order to preserve them for posterity. 

TELLURITE, A TELLURIUM OXIDE

The element tellurium is a silver-white metalloid (possesses properties of both metals and non-metals) with the symbol Te and the atomic number of 52 (number of protons in the nucleus of the atom). Tellurium exhibits oxidation states of 6+, 5+, 4+, 3+, 2+. 1+, 1-, 2-; however, only 6+, 4+ and 2- are stable. Tellurium can act as a cation with a 4+ oxidation state (IV) as in the uncommon mineral tellurite, TeO₂, or with a 6+ oxidation state (VI) as in jensenite, Cu₃TeO₆-2H₂O.   The telluride anion with a charge of 2- can combine with gold and silver cations in the minerals calaverite (AuTe₂) and sylvanite (AuAgTe₄); both minerals form major gold ores at Cripple Creek, Colorado.

Tellurium is an extremely rare element as most rocks contain about 3 parts per billion and is 8 times less abundant than gold. Tellurium is rarely found in a native form in rocks of the earth’s crust. MinDat listed 135 valid species containing essential tellurium: 1) 1 element; 2) 71 sulfides and sulfosalts; 3) 2 halides; 4) 44 oxides; 5) 13 sulfates; 6) 1 phosphate,1 vanadate, and 1 arsenate; and 7) 1 silicate.  So, most tellurium minerals are oxides and sulfates.

I previously posted about emmonsite (February, 13, 2017), a fairly rare iron (ferric) tellurite [Fe₂(TeO₃)₃-2H₂O], about the only tellurium mineral in my collection.  However, I recently picked up a specimen of the oxide tellurite, although certainly I feel out of my comfort zone in describing it. It was collected in 2000 by David Shannon (Arizona).

This is the best I can do with the photomicrographs!  The largest crystal (up or left), appears hexagonal and is only about .33 mm in length.  perhaps it is zemannite?  The dark green minerals attached to this large crystal may be denningite.  The really tiny acicular, straw yellow crystals are tellurite.

The specimen comes from the Moctezuma Mine (Bambolla) Mine, Moctezuma Municipality, Sonora Mexico.  It is a hydrothermal, gold-tellurium mine that produced a bonanza of tellurium minerals in the oxidized zone, something like 15 new species plus several previously named. The problem with my specimen is that all crystals are extremely small, less than one mm in length, and beyond the capability of my digital microscope.  However, they are visible (barely) in my binocular scope. The tellurite crystals are acicular or needle-like, light or straw yellow to light tan in color, less than adamantine in luster.  The tiny crystals are in “tuffs” or scattered, are translucent, and have a measured hardness of ~2.0 (Mohs). The quartz matrix also contains two other types of crystal that are larger and more robust than tellurite, and of a different color (green to brown), are striated, and some are terminated (pyramid-like).  My best guess is denningite [(Mn,Ca,Zn)Te₂O₅].  The other unknown appears to be hexagonal and might be zemannite [Mg₀.₅ZnFe(TeO₃)₃-4.5H₂O].  My mineralogical capability with these tiny crystals is lacking!  But, I have learned much from this little exercise.

Anyone who stops learning is old, whether at twenty or eighty. Anyone who keeps learning stays young. The greatest thing in life is to keep your mind young.  Henry Ford