Remember
in the mid-1980s when Buckyballs (buckministerfullerenes) came along? They were one of the first nanoparticles to
be discovered and are linked carbon atoms with the finished product resembling are
spherical soccer ball. Science was
buzzing with excitement. These molecules were named after R. Buckminster Fuller,
a noted architect and inventor who was credited with (at least in the U.S.) designing
and popularizing the geodesic dome. The
U.S. military was the first industrial user of the dome but the free spirits
(some would call them hippies) jumped on the bandwagon in the 1960s and dome
tents and commune building were popular.
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| The Climatron. Photo courtesy of its home, the Missouri Botanical Gardens. |
In
1933 Fuller designed, with three prototypes built, a dome-type care, the Dymaxion
that perhaps in the future could fly, land and drive—WOW. One might think that all construction in the
country would soon feature domes. But
somehow the “idea” slowed and today one might see geodesic domes in the forms
of tents, DOT sheds in areas of heavy snow, radar domes, biospheres, and some
construction companies/shops. However,
no cars and not many houses.
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| One of the prototype Dymaxion vehicles. Public Domain photo. |
However,
the carbon molecule buckeyballs were far more successful that the geodesic domes
and opened up the entire new area of nanotechnology—solar cells, 5G communication,
and a whole bunch of things I really don’t fully understand!
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| A sketch of the carbon buckministerfullerene. Courtesy of understandingnano.com |
As
the 21th Century rolled around innovative toy makers discovered that the term Buckyball
was not copyright so here came the kiddie toys of round magnets (super-strong,
rare earth neodymium magnetic spheres). The youngsters could now build
their own models of buckyballs, or a variety of other designs including the ubiquitous
refrig magnet to hold up crayon drawings. So, nanotechnologists to kiddies were
having fun with buckyballs.
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| Buckyball constructed with magnetic "balls." Photo courtesy dotpedia.com. |
But
rockhounds, being a playful bunch, could not let the designers, soccer players,
kiddos, architects, chemists, physicists, engineers, etc. have all the fun with
rounds balls made of whatever. We have
the geode hunters and sphere makers and even some cab designers having fun
playing with minerals. However, the most
fascinating minerals shaped like buckeyballs (spheres of some sort) are usually
only seen by rockhounds looking through a loupe or better yet, a scope! There is a fascinating world that is open to
micromounters, a view that is often missed by rockhounds. Now, I am not really a micromounter (they are
really skilled) but do enjoy taking a peek at tiny mineral specimens through my
binocular scope and snapping a photomicrograph or two through a
not-too-expensive digital camera (wishing I had focus stacking knowledge).
Di
I have fun looking at little round balls?
You betcha! The other day
(celebrating firecracker day sequestered in my mineral den) I was looking at a
specimen labeled beuranite, an iron phosphate, collected from the Coon Creek
Mine in Polk County, Arkansas. Something
seemed wrong for beuranite identification so I looked on MinDat and the mineral
was no longer listed—for any locality in Arkansas. What I did notice was that the mineral in
question was cacoxenite, an iron aluminum phosphate [FeAlO6(PO4)17(OH)12-75H2O].
Cacoxenite is often a quite attractive mineral in various shades of yellow to
orange to golden to green. And, the tiny acicular crystals (crudely hexagonal,
subviterous) are often found in concentric spherical aggregates. In other words, lots of little cute balls. Cacoxenite is a secondary mineral (like many
other phosphates) in the oxidation zone of ores of iron. At Coon Creek Mine the mineralization is in
fractures of novaculite (fine grained siliceous rock).
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| Acicular crystals of cacoxenite found in spherical aggregates. Each "ball" is less than 1 mm in diameter. The matrix is probably some iron phosphate. |
At
the same time I was looking at the Arkansas specimens I picked up a stray on my
desk labeled leucophosphite from the Czech Republic. As a curious sort of person, I stuck the
specimen under the scope expecting to see a reddish-orange mineral (I did, the
leucophosphite) but also observes a passel of “little balls.” At first glance
one might think insect eggs-nope, a bunch of spherical minerals. Somewhere in
the back recesses of my mind I recognized the mineral so off I go to MinDat to
confirm it was meurigite. Actually the
people in the know have added a k on the end (meurigite-K)
to distinguish the potassium dominant form from the sodium dominant meurigite-Na. The mineral is another of those potassium
iron phosphates [KFe8(PO4)6(OH)7-6.5H2O]
that only Tom up at Dakota Matrix can distinguish apart.
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| Submillimeter spheres of acicular crystals of meurigite-K on a matrix of black goethite? (bottom) and red to red-brown leucophosphite (upper two photomicrographs). Leucophosphite is another hydrous potassium iron phosphate. |
Meurigite-K
is yellow to yellow-green to yellow-brown to white in color composed of radial
acicular sprays that usually show a concentric pattern on the inside of the
spheres. My specimen came from Těškov, Rokycany District, Plzeň Region, Czech
Republic.
As
noted above many phosphate minerals have this spherical appearance with
acicular crystals radiating out from a center.
As with many phosphate minerals, I failed to fully (or even partially)
understand their mineralogy or provenance.
Most of these “little balls” are secondary occurrences in the oxidized
zone so I assume that primary phosphate minerals were the original source. As for the “cause” of these “little balls” of
radiating crystals, it is one of life’s persistent questions that is above my
skill level of understanding.
The
fact that you are willing to say, “I do not understand, and it is fine,” is the
greatest understanding you could exhibit. Wayne Dyer