TUCSON GEM AND MINERAL SHOW 2018

TUCSON GEM AND MINERAL SHOW: 2018

The” granddaddy” of the Tucson venues is the Tucson Gem and Mineral Show® finishing off a spectacular two weeks.  I usually attend the opening day (February 8, 2018) and the crowd was large and the displays spectacular.  The Show, as do most club shows, features both guest display/competitive cases of minerals, and booths occupied by several hundred dealers (~250).  A big difference between TGMS, and a local show such as CSMS, is that high-end dealers from around the word bring their finest specimens to Tucson.  The prices for these museum-quality specimens ranges into 7 figures (and are usually marked POR, price on request).  However, just ogling at these one-of-a-kind mineral specimens is well worth the entire trip to Tucson.

It also should be noted that TGMS sponsors several lectures and symposia throughout the week and these are free to the public (admission charge for the other parts of the Show).  There is a Saturday night program with a silent auction, buffet dinner, an awards ceremony, slide competition awards, and a voice auction.  On Thursday the Micromount Room was open and Friday brings the Author Roe Memorial Micromount Symposium. 

Since it is really tough to write much about the TGMS, most of this article is composed of photographs.  But remember: 1) the Show is overwhelming with the number of exhibits and cases; 2) virtually every mineral is behind glass and that fact affects photographs. 

A single row of dealers in the Exhibition Hall (contains both dealers [minerals, books and jewelry] and the display cases).  The Arena section is another part of the Convention Center houses ~100 mostly jewelry dealers.

Legrandite, a hydrated zinc arsenate, is one of my favorite minerals.  This specimen was provided by the Miner’s Lunchbox and collected from Level 7, Saint Judas Chimney, Ojuela Mine, Mapimi, Durango, Mexico.  One could purchase the specimen for $35,000.

                                                                         

Gold is always a popular element/mineral at the Tucson Show.  The lower photo is from The Collectors Edge in Golden, CO. and has a Price-on -Request note, POR).  The upper photo of gold is courtesy of the Miners Lunchbox and is POR. 

This amazing specimen (~3 feet in length) of gypsum v. selenite (hydrated calcium sulfate) greeted visitors near one of the entrances.  POR with a phone number and from China (where?).

Not all booths had minerals “for sale.”  Rock of Ages had a wide variety of mining paraphernalia for buyers.

Like agates?  Look no further than this giant, polished Laguna agate, from the Alianza Claim, Estacion Ojo Laguna, Chihuahua, Mexico.

I kept thinking about the number of rings available from “The Largest American Turquoise” taken by Jack Wigley from the Mona Lisa Mine on Little Porter Mountain, Polk County Arkansas.

Unfortunately, readers cannot read the print from this photo; however, I stared at the display for a long time trying to gather facts about twinning in minerals. The display was constructed by the American Museum of Natural History.

Here is another quite informative poster from the Smithsonian Institution National Museum of Natural History.

 And finally, the third informative poster that I studied in detail—Classes of Mineral Symmetry.

This image should be recognizable to readers of the Pick & Pack:  microcline v. amazonite (potassium feldspar) and quartz v. smoky from the White Cap Pocket, Smoky Hawk Claim, Teller County, Colorado.  Display by Collectors Edge.

  

 

Pseudomorph of agate (silicon dioxide chalcedony?) after aragonite (calcium carbonate).  Collected from Rancho Coyamito Norte, Chihuahua, Mexico.

I thought this was a beautiful display of turquoise (copper aluminum hydrated phosphate) jewelry. 

This is an interesting display of German minerals and German mugs (with a mines motif).

This is an interesting specimen of stibnite, an antimony sulfide.  There was no listed locality information, but I am guessing Romania.

This case was a fabulous display featuring a variety of agates.  One must read the small locality slips in order to get more complete information but what an interesting case.

These two photos present one of my favorite minerals—amber barite (barium sulfate) collected from concretions in the Pierre Shale (Cretaceous) along Elk Creek in western South Dakota.  My collected specimens are not nearly as impressive. The upper photo also has yellow calcite crystals.  Both specimens are courtesy of The Collectors Edge.

The Collectors Edge displayed this beautiful specimen of zoisite v. tanzanite (calcium aluminum hydroxyl sorosilicate) from Tanzania. Rhodochrosite (manganese carbonate) from the Sweet Home Mine near Alma, Colorado, is in the background.

Specimens of the Tourmaline Group were in several displays and included ilvaite above and elbaite below.

I talked to CSMS member Jack T. and was informed that he and Kaye had a competitive case of pyrite.  Was this their case?  

And finally, something sort of whimsical—a calcite sphere on quartz points (covered with dolomite? druse) collected from the Boldut Mine in Romania.

I could have inserted a gazillion more photos; however, the attention span of most persons just wanders, and their eyes begin to water, after watching and reading so much of my chatter.  So, I leave you with a pleasing sunset view from the campground--west escarpment of the Superstition Mountains.. 

                                                                          

CARROLLITE (COBALT-NICKLE SULFIDE): TUCSON PUEBLO SHOW

Another large venue with a variety of dealers is the Pueblo Gem and Mineral Show held in the Riverpark Inn area west of the Interstate.  Here hundreds of deals hawk everything from beads to rocks and minerals to fine jewelry.  I examined most of the booths except the scattered dealers that were wholesale only areas. Some show dealers situated were in large free-standing tents such as the table below in a large area of Madagascar dealers while other, more local dealers, erected small shelters about 10 x 10 feet.  I found these smaller dealers much more personable and willing to visit about their minerals.  I fact, I picked up small green and blue tourmaline crystals from one.  However, most dealers (hundreds of them) were tightly packed into the “main pavilion tents.”  After gazing at the merchandise, mostly jewelry and metaphysical paraphernalia, for a few hours everything began to look the same and it was time to bail.

One of the well-stocked tables of "lots of things" displayed in a large tent occupied by dealers from Morocco.

A table of absolutely gorgeous slabs of cut and polished labadorite (a potassium feldspar, semi gemstone).

You can take your quartz home polished as a sphere or in large crystals.

Besides the tourmaline crystals noted above I picked up a hand sample of crystalline calcite containing several shiny, metallic-looking crystals of a copper cobalt/nickel sulfide [Cu(Co,Ni)₂S₄].  Somewhere in the back recesses of my mind a little card popped up and said, “copper sulfide, check Butte notes.”  In doing so, I remembered reading about carrollite when writing about the Butte, Montana, sulfides of covellite, djurleite, chalcocite, and digenite.  Although common at some African localities, it seems not present at two famous covellite [CuS] localities in the United States, the Leonard Mine near Butte, Montana and the Summitville District in Colorado. 

The photomicrograph does not do justice to the mirror faces of this altered cube, maybe a cubo-octahedron., of carrollite (C). A gemmy poker chip of calcite (Ca) is attached at lower right.  The calcite rhombs (CA) form the matrix.  I don't have the slightest idea what the small green crystals (?) scattered on the matrix represent. Width of carrollite crystal ~3.2 mm.

Close-up, at least as close as my camera will permit, of tiny, cloudy, greenish?, submillimeter crystals on matrix. 

~ 3 mm modified cube crystal of carrollite on calcite matrix.

~3 mm. modified cube of carrollite.  The Ch is a distant particle of chalcopyrite (Ch).

This is carrollite but it is massive and without crystal forms.

More massive carrollite but a larger hunk of chacopyrite (Ch) along with the unknown ? tiny ??cubes.

Carrollite has a bright silver color (sometimes more steel in color), a very definite metallic luster (often mirror-like), a hardness of ~4.5 (Mohs), a gray-black streak and virtually no cleavage or fracture pattern (uneven). Crystals belong to the Isometric System and often appear as modified cubes.  Although I do not understand the occurrence, some pods of carrollite in the calcite matrix appear to resemble melted “blobs.”  Unlike many other copper sulfides, carrollite does not seem to tarnish.

 Carrollite has some interesting solid solution partners (Wagner and Cook, 1999).  The copper in carrollite has a valance of +1 while the cobalt has a +++3; however, in one solid solution series Co++ can substitute for the monovalent copper + so we go from Cu⁺(Co,Ni⁺⁺⁺)₂S₄ to Co⁺⁺Co⁺⁺⁺₂S₄ [also noted as Co₃S₄], the mineral linnaeite.  I wish to be a better chemist and understand how that change works!  Carrollite occurs in hydrothermal veins along with many other copper sulfides but there must be some sort of phase relationships (temperature, pressure) that govern its crystallization.

My specimen of carrollite came from the Kamoya South II Mine, Kamoya, Kambove District, Democratic Republic of the Congo.  This large open pit mine evidently produces most of the carrolite specimens coming from Africa (or from any place).  The mine is located in the Katanga Copper Crescent and further situated in the larger Central African Copper Belt.  The ore bodies in the Kambove District are hosted by late Precambrian metasedimentary rocks associated with fold and thrust faults in a rifting basin.  Although the cobalt content in carrollite is not high, it was/is a major ore mineral at the mine.

One little bit of trivia here, linnaeite, the close relative of carrolite was recently discovered in newly formed rocks of the Mi-Atlantic Ridge (Lee and others, 2002).

REFERENCES CITED

Wagner, T. and N.J. Cook, 1999, Carrollite and related minerals of the linnaeite group: solid solutions and nomenclature in light of new data from the Siegerland district, Germany. Canadian Mineralogy vol. 37.

Lee, S. Y., Watanabe, M., Hoshino, K., Oomori, T., Fujioka, K., and P. A. Rona, 2002,. First report of linnaeite (Co₃S₄) and millerite (NiS) from active submarine hydrothermal deposits: Rainbow hydrothermal field, Mid-Atlantic Ridge at 36˚ 14'N. Neues Jahrbuch für Mineralogie-Monatshefte, vol. 1.