Snapshots from the Tucson 2002 Gem and Mineral Show
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Hey rockhounds, greetings from Tucson and welcome to my online Tucson 2002 Gem and Mineral Show report!

Ammonoidea 2002 I
Arizona Mineral and Fossil Show at the Ramada Inn - Feb 3 to Feb 16 - 1601 North Oracle - 520.623.6666

Tuesday, Jan 29th - Although the Arizona Mineral and Fossil Show at the Ramada Inn does not officially open until Monday, January 3rd, I have come to appreciate that many of the dealers at this show arrive and set up early, and that the early birds get the ammonites...

I think Mineralien Zentrum, a German fossil dealer in Room 184, was the first dealer set up and open at the Ramada Inn this year. The show at the Ramada Inn is open to the general public and this is The Show at Tucson for fossil dealers and collectors alike. I couldn't help but notice Mineralien Zentrum had tables of ammonite specimens set up outside in front, so of course I had to pay them a visit.

Depicted at left with a close up above are Dactylioceras sp. ammonites in country rock from Schlaifhausen, Germany. Mineralien Zentrum showed several large tables covered with these Dactylioceras specimens out on the lawn in front of their room. Dactylioceras was a widespread genus of ammonites from the Jurassic Period of the Mesozoic Era. (If you are a little rusty or hazy regarding the nomenclature of geologic time here's a little help.) Dactylioceras are abundant throughout Europe, with exceptionally fine Dactylioceras specimens sourced by England and Germany. Horizons containing mass mortalities such as these specimens suggest that these ammonites may have died after shortly after spawning. There were 60+ pieces up to 2 feet or so across here, which were offered as a take all wholesale lot for $3000.

Shown at right is another table out front covered with Arietites sp. ammonite specimens. As a genus Arietites is characterized by often very large evolute shells exhibiting subquadrate whorl sections and pronounced, near-rectiradiate ribbing on the flanks. These are from Balingen, Württenberg, Germany and the Lower Lias formation, which dates them from the Lower (early) Jurassic.

These Arietites specimens ranged in size from about 6" to 12" and I saw prices on them ranging from $190 to $350. A significantly larger specimen at about 18" in diameter on the corner of this table wanted $950.

Just inside the door at Mineralien Zentrum was a table covered with Jurassic nautiloid specimens from Scunthorpe, Humberside, England. Depicted above right is a pretty specimen typical of the nautiloids covering this table, which ranged in price from about $260 to $420. This one was approximately 5" in diameter and wanted $300. The country rock had been nicely prepared in such a manner on these so as to provide a natural display stand, which I think a plus.

The Nautiloidia were contemporaries of the ammonites and are closely related. Ammonites are thought to have evolved from an ancient nautiloid more than 400 million years ago during the Silurian Period of the Paleozoic Era. However, unlike the ammonites which did not survive the mass extinction at the end of the Cretaceous Period of the Mesozoic Era that also took out the dinosaurs, the nautiloids are extant with the single modern genus Nautilus surviving in today's oceans. The modern nautilus (shown at left) is the only surviving shelled cephalopod and is probably the descendant of the nautiloid Eutrephoceras.

The process of fossilization is such that hard parts like bones, teeth, scales and shells are favored, and detail from soft tissue is rarely preserved. The contemporary nautilus provides models and a basis for making inferences regarding how their shells functioned as well as the bodies and soft tissues of now extinct species of both nautiloids and the ammonites. While there are many similarities between nautiloids and ammonoids, the ammonites appear to be more closely related to modern octopi and and squids. Modern squids and particularly octopi appear to have descended from various ammonites during the Cretaceous Period.

There was a significantly larger and exceptional Scunthorpe nautiloid displayed on this table which is shown at right. This specimen was approximately 12" across and was mounted and presented on a stand, having been cleaned of country rock. It had already been sold to another early bird dead cephalopod appreciator at a price approximately an order of magnitude higher than the smaller and yet unsold specimens and keeping it company on the table.

The ganoid scaled Lepidotus sp. specimen depicted above and at right is an impressive fossil fish and irresistible as a photographic subject.

Ganoid scales are usually rhomboid in shape and have articulating peg and socket joints between them. They are a "primitive" type of scale found on some extinct fossil fish such as this Lepidotus sp. and also on extant fishes such as modern paddlefishes, gars and sturgeons.

This specimen was about 24" in length and presented on a rectangular plate that was approximately four feet by two feet. It is from the Upper Lias formation and Jurassic Period, Holzmaden, Württenberg, Germany, and was commanding $25,000.

Shown above left is a particularly aesthetic and large Somerset, Great Britain Asteroceras sp. ammonite specimen from the Lower Jurassic. This Asteroceras is pushing a foot in diameter and was prepared with a nice stand fashioned from the country rock. To my eye the suture patterns on this specimen stand out handsomely with the lighter colored material providing a nice contrast. This Asteroceras wanted $3500 to take home.

Depicted above right is a pretty group of Jurassic Vemiceras sp. ammonites in country rock. These are from the Lower Lias formation, Bristol Channel, Somerset, Great Britain. This specimen is about 13" across and the largest ammonite is about 4.5" in diameter. I thought the three dimensional relief and overall preparation of this piece attractive and Mineralien Zentrum related that it came from an old collection. This piece was priced at $395 and it went home with a couple from Boston just a few minutes after I photographed it. Early birds...

Shown above are two of the fossil crabs which were shown in a case in Mineralien Zentrum's room. Both these specimens are from Verona, Italy. These date from the Eocene Epoch of the Tertiary Period and are approximately 40 million years old. The specimen depicted above left is a coral crab, Ranina Marestiana. Its carapace measures about 2" x 1" and the fossil tops a country rock stand. It was priced at $3,400. Depicted above right is a beach crab, Harpatocarcinus sp. It is carapace measures about 4" x 2 3/4" and it was also prepared on a stand of country rock which was about 12" across. This Harpatocarcinus wanted $3,500.

Depicted at left and above is an approximately six foot by four foot plate featuring four Pentacrinus sp. crinoids from the Upper Lias formation, Holzmaden, Württenberg, Germany. I thought the way the stems appeared to intertwine on this specimen particularly attractive. Just to the left of the crinoids on this plate is a belemite fossil, which Mineralien Zentrum will no doubt throw in for free when you purchase the crinoids for $45,000.

Mineralien Zentrum, Ramada Inn Room 184 - WWW: www.mineralienzentrum.de Steintwiete 11, 20459 Hamburg, Germany - Phone: 040/369003-11 Fax: 040/369003-10


Thursday, Jan 31st - The winter storm visiting Tucson provided what the one of our local TV weathermen described as the first measurable snow in 11 years. He must be in a different part of town than I am, but this morning it was 26° with the cars, streets and sidewalks coated with ice in my neighborhood. It can be rather dangerous out on the streets after a rare winter storm like this in Tucson, as many of the locals are without a clue when it comes to driving on ice or snow, and there were a lot of fender benders early this morning. However, the storm departed last night and today it was sunny and warmer. En route to the Ramada Inn I stopped by at the Mineral and Fossil Co-op next door to check out the polished Madagascar ammonite fossils at DocFossil, as they were still busy setting up at the Co-op when I visited at Ron Coleman Mining yesterday.

DocFossil is a wholesale operation sourcing a good deal of lapidaried Madagascar and Morocco ammonites. Shown above left is a box of polished Madagascar pieces ranging in size from about 3 to 5 inches across and priced from about five to twenty-five bucks each. The piece showing in hand above right was about 3 inches across and priced at $10.

Whatever external detail that may have been preserved on the shells of these fossil ammonites has been ground away and lost to the polishing process. While doing this can make for an attractive rock and decorator piece, the external detail and condition of the conch is of utmost importance to most ammonite collectors, as it is the external detail in conjunction with the locality which is typically used to identify the ammonite. There are significant retail markets for these polished pieces - probably much larger than for collector grade specimens. I'm not so sure of this, but I at least like to think that the best of these are preserved as fossil specimens with the otherwise unmarketable material putting food on the table for the native lapidaries enroute to retail markets.

While they are pretty and inexpensive enough, I haven't yet purchased a polished Madagascar piece like this for myself and my own fledgling ammonite collection, but I'll probably get around to that when I find one that particularly likes me. I do see some redeeming value in these from a collector's and particularly an ammonite display perspective and wouldn't mind having a more familiar shaped piece to compliment a polished Baculites sp. section from from the Cretaceous Pierre Shale in Wyoming that I acquired from a Ramada Inn dealer during the Show last year.

Polishing like this can dramatically reveal the intricate and often beautiful suture patterns preserved in the fossil ammonite which are often not evident in collector specimens where the external detail obscures these interesting structures. Suture patterns can also be used for identification as they are species specific, but it takes a real ammonite expert to interpret and identify ammonites by their suture patterns.

DocFossil also displayed an extensive selection of sectioned and polished Madagascar ammonites, which are also very popular retail rock shop and decorator items. These Madagascar pieces are typically filled with calcite. Sometimes the conchs are filled all the way through and sometimes the chambers in the phragmocone contain open vugs lined with calcite crystals with rather attractive effect. You can acquire an ammonite and a calcite, two for one...

These sectioned ammonites ranged in size from about 6 to 12 inches across and I saw prices ranging from about $40 to $150 per pair. These can also do a nice job of illustrating and showing off the internal structure of the ammonite's conch as well as just sitting around and looking good...

I acquired a sectioned Madagascar pair prepared from a Phylloceras sp. fossil from a dealer at the Ramada Inn several years ago when I first began assembling my ammonite collection. These Madagascar pieces are fairly ubiquitous at Tucson and I think a nice pair of these is just about a must have for an ammonite collection and display. You will sometimes see single pieces for sale but to my way of thinking a pair is the only way to go. I really enjoy mine and will probably get around upgrading them or possibly adding another at some point in the future. Somewhat less common are pyritized pieces from coming from Europe and Russia which can be rather spectacular when sectioned and displayed in this manner.

DocFossil (Sahara Sea Collection), Mineral and Fossil Co-op - WWW: www.docfossil.com - 1635 N. Oracle Road, Tucson, AZ 85705 - Phone: (520) 617.0207


Here's a couple of Texas ammonites, Calycoeras tarrantense from the Cenonmanian Stage of the Upper Cretaceous, Arlington Member of the Woodbine Group, Dallas County, which were shown by Scott Taylor of Renaissance Fossils in Room 176 at the Ramada Inn. The specimen shown in hand above left was about 5 inches in diameter and it was asking $200. Note the embracing calcite veins which were preserved by the preparer. The Calycoeras depicted on a stand above right was larger at about 8 inches in diameter and it wanted $200.

Through seeing similar Calycoeras tarrantense specimens which were shown at Tucson last year by Renaissance Fossils, I've become interested in an expedition to Texas one of these days to collect marine fossils in this and other Cretaceous formations in Texas. Last year I managed to get a standing invite from a Texan who collects Calycoeras from this locality and needless to say I'd like to field collect a nice one for myself.

BTW, if you are also interested in researching and collecting Texas Cretaceous ammonites or Cretaceous ammonites in general, you are in luck as there is a fantastic reference available on them which is published by and available from the Paleontology Section of the Houston Gem and Mineral Society. Texas Cretaceous Ammonites and Nautiloids is a voluminous 439 page tome and exhaustive reference describing 260 genera and 604 species of Texas Cretaceous ammonites and nautiloids along with detailed information on the stratigraphy and formations in which they are found.

This reference contains profuse illustrations and an illustrated glossary of technical terms is also provided which I have found very useful in deciphering and grokking ammonite speak in general. And the really good news is this book costs only $18.50! If you are interested in ammonites and don't yet have a copy of this one in your own library, I am very confident you will consider this book an excellent value and recommend it highly. And if you should want or need yet more information on Texas Cretaceous ammonites and nautiloids, the reference section of this book lists more than 500 related papers and publications...

While checking out the Texas ammonites I couldn't help but notice and admire this fossil Labidasaurus hamatus on display at Renaissance Fossils. A quater helps provide some scale for this specimen, which carried an $8000 price tag. Labidasaurus was an early reptile from the Lower Permian and this one was recovered from the Arroyo Formation, Lawton, Oklahoma. The Permian was the last period of the Paleozoic Era and began 285 million years ago, spanning the last 40 million years or so of the Paleozoic. Although the Permian began as a tectonically quiet time characterized by lowland swamps and fern jungles with near-tropical climates, intense mountain building and glaciation took place during the Permian. The Appalachians are one of several mountain ranges that developed during the Permian, precipitated by the Earth's continents colliding and forming the supercontinent Pangaea. The climatic effects of this orogeny produced vast areas of dry continental interiors with extremes of temperature probably not previously known in the history of terrestrial life on Earth. The Permian was a time of major evolutionary change and development for animals, which saw the rise of the amphibian labyrinthodonts as well as primitive reptiles, among which was Labidasaurus hamatus.

When I inquired how much restoration had been done on this specimen I was informed by proprietor Scott Taylor it was all Labidasaurus hamatus, but not all from the same individual. Depicted above right is a specimen of the country rock with fossil lizard parts which Scott brought out to share and illustrate what the preparer starts with in putting one of these together. If you look closely you should be able to make out some jaw parts and teeth towards the center of this photograph. Scott related that to makes things really interesting, it is not uncommon to have fossilized parts from other animals mixed in... Kind of gives you some appreciation for the work that goes into reconstructing and preparing a specimen like this and why it costs $8000, huh?

Labidasaurus hamatus, an Early Permian reptile from the Arroyo Formation, Lawton, Oklahoma

Renaissance Fossils, Ramada Inn Room 176 - Email: rfossils@hotmail.com - 217 E. Linda Drive, Garland, TX 75041 - Phone: (972) 278-0473


I found some more early Permian reptile fossils at Geo-Expert in Room 162 at the Ramada. Geo-Expert was showing twenty or so plates featuring some handsome carbonized specimens of Discosauriscus pulcherrimus. These were first found near Boscovice in Moravia-Czech Republic in 1872. The country rock where these occur is described as a gray spotted, strongly bituminous pleocarbonate shale about 10 inches thick in a group of sandy, clayey gray Permian beds. The specimen shown above right featured a fossil about 8 inches in length on a plate that was about a 12 inches overall. These carbonized fossils were produced when subsequently deposited sediments built up over the Permian beds and the weight of the overlying rock compressed them, producing a sort of geological road kill. I thought this one the best of the lot and it was priced at $800.

Also displayed at Geo-Expert were this group of Scyphocrinus elegans fossils of a crinoid with worldwide distribution that lived about 400 million years ago and which marks the border between the Silurian and Devonian periods of the Paleozoic Era. This was a free swimming species of crinoid with its column terminating in a floating ball instead of gripping structures. I noted a pretty wide spread of prices on these crinoids which varied with size and quality and ranged from about $45 to $2500.

Above left and right are some close ups showing off some detail from one of the specimens. This beautiful crinoid was once abundant in uppermost Silurian and lowermost Devonian seas. Fine specimens of Scyphocrinus elegans such as this one are found in Morocco, where a mass extinction caused a horizon of these to accumulate in ancient marine sediments. At about 10 inches overall, the specimen depicted above was one of the smaller in the group offered by Geo-Expert but it had exquisite detail and was also one of the more expensive of the lot, priced at $1200.

Geo-Expert, Ramada Inn Room 161 - WWW: www.geo-expert.de - D-31319 Sehnde OT Evern, Germany - Phone: 05138/2988 Fax: 05138/3816


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