MILLISITE THE PHOSPHATE & 22ND STREET TUCSON 24

 

Well, 2024 is here!!  No, not the 1^st of January but the opening of mineral, fossil, bead, and rock venues associated with the annual Tucson Gem and Mineral Show (the main event). Best known simply as Tucson, the “main event” is scheduled for February 8-11 at the downtown Tucson Convention Center; however, there are somewhere around 50 other shows scattered around the city. These secondary (and I use this term loosely) range in size from ~10 dealers to the “giant” shows with more than 300 dealers. I don’t have the slightest idea about the total number of dealers; however, 2500 are listed in the Tucson Show Guide, and there are probably hundreds of “deals” consummated over dinners or in a hotel rooms. The Rock Yard opened January 16^th and will close on February 9th while Just Minerals and Crystals opened for three days over a weekend. Most of the larger shows seemed to open around the 25^th and 26^th.  The first event (sort of event) I attended on January 22^nd and was an unlisted “sale” of flats, greatly reduced in price, at the warehouse of Shannon’s Minerals. Since I am not a dealer, I really did not need a flat of calcite specimens! But I had fun just looking.

The entrance to the north end of the tent: three walking aisles with "booths".

My first major show attended was the “giant” 22^nd Street venue. Here ~300+? dealers are crammed into a series of very large tents hooked together, or in very close proximity and stretching about a fifth of a mile. The show reminded me of the old Clint Eastwood movie, The Good, the Bad, and the Ugly. The “ugly was the parking situation. Past visitors know the gravel parking lot is adjacent to the tents, full of large potholes, and this year was full of water! The concessionaire gets your $10 fee going in the gate and then one hopes for a vacant space. During my visit I was in a large line of cars essentially going around in a circle as virtually no one was leaving the show at 10:20 a.m. and empty spaces were unavailable. For some unknown reason the car valet stopped in front of my vehicle and said, “we just found two spaces down at the end—head that-a-way” and so I splashed quickly thru the mud and water to the empty space. There were still 30 or so vehicles in line with no empty space “that-a-way” and more arriving thru the gate. Tempers were flaring, drivers were shouting, and the care valets were throwing up their arms. I quickly parked and disappeared into a tent.

 

The devil, or maybe a cast (of me) from one of my former students???

Above three photos: fish and palm fronds from the Eocene lake beds of the Green River Formation near Kemmerer, Wyoming.

A little paleo, sort of.

And better vert paleo.

No rock and mineral show is without plenty of beads.

Golden Hills Turquoise is "rare, unique, and pricey" and is found in the Altyn-Tyube mine in Kazakhstan.

A nice stibnite beyond my price range. But nice to see a mineral.

And what do we have here? Minerals? Fossils? Rocks? Beads? Who knows.

Finally, a few minerals. None interest me.

Big spheres or small spheres. You pick.

And of course some mats so your specimens don't scratch the coffee table.

For the “bad” scene I offer a quote from a MinDat reader and commenter, for us, 22nd Street was mostly a bust. For the most part though, it seems these shows have turned into more trinket/metaphysical fairs than places for mineral specimens. And I say, Amen brother, Amen. 

For the “good” stuff, I did have a nice visit with a Pakistani dealer I purchased from in past years; however, nothing really caught my eye this year.  I also talked a little paleo with Craig from Rocky Mountain Dinosaur Resource Center in Woodland Park, Yooper minerals with Michigan Rocks and Minerals, and Colorado minerals with Amanda at USA Mined Gems and Minerals. And I came home with two small silver chains (for future gifts), and a perky box on a busy shelf with a lonely looking mineral. However, the “best of the good” was the Curry Pot food trailer parked in the lunch area. I await their Sri Lankan food each year. I suppose, that in retrospect, it was a pleasant way to spend a January day.

The Curry Pot. Amazing lunch.
 

My lonely perky box contains sort of an average specimen of crandallite,  a rather uncommon hydrated calcium aluminum phosphate [CaAl₃(PO₄)₂(OH)₅-2H₂O] that often is associated with the phosphates variscite and wardite.  I suppose that when most rockhounds think about collectable and colorful crandallite and variscite, the Little Green Monster Mine in Utah County, Utah, pops up, along with the names Ed Over and Art Montgomery.  Over was a mineral collector from Colorado Springs and teamed with college professor (Lafayette College) and mineral dealer Art Montgomery.  Together in a few short years the dynamic duo brought to market and museums pounds/tons of spectacular mineral specimens including topaz from Pikes Peak, red wulfenite from the Red Cloud Mine in Arizona, various minerals from the high-altitude Mt. Antero, Colorado, green epidote from Prince of Wales Island in Alaska, and the variscite from Fairfield, Utah (near the south end of the Oquirrh Mountains).  They worked the Little Green Monster Mine for a few short years in the late 1930s and brought out the colorful phosphate nodules by wheelbarrows.  Today the mine is closed (maybe-maybe not), and virtually all Little Green Monster Mine specimens are decades old, and many are really quite expensive (four to five figures).  My specimen seemed like a real bargain!

Variscite [AlPO₄-2H₂O] is the original phosphate and formed in dense microcrystalline nodules with trace amounts of chromium and phosphorous imparting the green color.  Crandallite seems the first alteration mineral to form as variscite picks up and adds calcium from solution.  Normally colorless, trace iron gives the Utah crandallite a yellow color.  Numerous other exotic phosphates such as wardite, englishite, gordonite, millisite, montgomeryite and overite are also present at the Little Green Monster. I specifically purchased this perky box due to the presence of millsite with the crandallite.

White, milky, crusty millisite with "gray" wardite. Width FOV ~6 mm.

Botryoidal crandallite with white splotches of millisite. Width FOV ~6 mm. 

Lots of tiny phosphates with botryoidal crandallite, some white millisite, green variscite, some gray wardite, and who knows what else. Width FOV ~5 mm. 

 Millisite is another one of those rather rare secondary phosphates that attracts the attention of collectors simply because it is “there.”  Unlike many of these other secondary phosphates millisite is colorless or chalky white in color, perhaps even a washed-out light green—really not a very pretty mineral. Under very high magnification millisite shows crystals composed of fibers; however, with my microscopes and magnification I really am unable to observe these fibers. Millisite [(Na,K)CaAl₆(PO₄)₄(OH)₉·3H₂O], like crandallite and variscite, is a hydrated phosphate (note the  H₂O in the chemistry). Millisite is sort of the forgotten, plain looking guy in the sliced and polished phosphate nodules from Fairfield. It is closely related to wardite, a mineral that seems to lack sodium and calcium (as found in millisite). Wardite often shows small crystals that are unlike the spherules and crusts of millisite. However, the gray to clear wardite often occurs directly with millisite and is very tough for an old plugger like me to identify. At any rate, the nodules from Fairfield/Clay Canyon have a fascinating array of minerals.

Although best known as a minor constituent from Fairfield, I located a 1960 article (Owens, Altschuler and Berman) describing “ millisite…and crandallite…[as]  major components of the aluminum phosphate zone of the Bone Valley formation of west-central Florida, where they occur as a microcrystalline intergrowth composing the cement in the altered phosphorite.”

REFERENCES CITED

Owens, J.P., Z.S. Altschuler, and R. Berman, 1960, Millisite in phosphorite from Homeland, Florida: American Mineralogist, vol. 45, no. 5-6.

Sometimes all you can do is say, WOW. Kevin Henkes