Denver Mineral Show - Part 3 - DGMS Show

21 September 2010


The Denver Gem and Mineral Society show is held in the Merchandise Mart, not far from the Holiday Inn which holds the Colorado Mineral and Fossil show. This is a club run show, and has a great family feel to it, with many displays from local collectors including children and families, and activities to encourage kids in the world of minerals. The show has many exhibits - this year's theme was Creede Mining District, Colorado - and also has talks each day.

Set up for the show was Thursday, opening to a steady crowd on Friday morning.

Our booth came together on time, we have three adjoining rooms to make one large space with over 12 cabinets of minerals, plus 4 sets of drawers of minerals, so it is a full day's set up to get everything arranged.

Our booth

Our booth

     To see a video of our best minerals, please click here.

Specimens on display
Silvers, Red Beryls, Rhodochrosites, Native Leads, and a wonderful blue Fluorite on display

Gem minerals
Gem Minerals

We had a wonderful selection of Chrysoberyl var Alexandrites from Fort Victoria, Zimbabwe on display with very well formed sixling cyclic twinning.

Arizona Minerals - the bottom two shelves were specimens from the E. O. Stratton collection, with information on Stratton and his collection.

Next door to us are The Collector's Edge. They had on display new Rhodochrosites from the Wuton Mine, Wuzhou Pref., China. These specimens have been found in the last 4-6 months. This mine has been producing rhombohedral Rhodochrosites that look similar to specimens from the Sweet Home Mine (same great colour and associations with purple Fluorite and sulphides) since around 2006. The miners have now driven down 100 feet below where the rhombohedral Rhodos were found, and are now finding Rhodos in flattened discoidal form of the same colour. There are still some rhombohedral crystals being found at this level, and the association with pale purple Fluorite is still occurring.

Rhodos from China
Pretty in Pink - new Rhodochrosite from Wuton Mine, China

Rhodos from China
Rhombohedral Rhodochrosite with purple Fluorite - centre specimen, with two smaller discoidal crystals at the front

Rhodos from China
New flattened discoidal Rhodos, two with purple Fluorite from China.

The Collector's Edge are recently back from their big exhibit in Bejing, China and had a case of the minerals that were on display - the labels were in both English and Chinese.

Richard and the Bejing Minerals
Richard Jackson and the case of minerals from the Bejing exhibition

Minerals from Bejing exhibit
Malachite to the left, and Adamite to the front, with the book that accompanied the exhibition.

Onto to Mineral Zone's room, Marcus Origlieri had a display of minerals from Ojuela Mine, Mapimi, Mexico, which included many raritites found in the last two months. The specimens were combinations of Mimetite (gemmy clear crystals) with Tsumcorite (little brown spearheads under the microscope) and Segnitite (yellow green). Marcus has confirmed the minerals by both x-ray and microprobe. Tsumcorite has been reported before from Mapimi, with at least one known specimen; and Segnitite had been found previously in 2002, but not to this extent. Marcus has approximately 7 flats of specimens from this find of Tsumcorite and Segnitite. The specimens were found at Campo Sur which is far away from where the Adamite is found at Ojuela Mine. The miners are searching the area for Galena for the associated Silver. They found this pocket of specimens with a Galena in the middle.

Mimetite, Mapimi, Mexico
Mimetite (clear sparkling crystals) and Segnitite (yellow green crystals) from Campo Sur, Ojuela Mine, Mapimi, Mexico.

Mimetite and Tsumcorite, Ojuela Mine, Mexico
Mimetite (colorless sparkling crystals) and Tsumcorite (yellowish brown crystals) from Campo Sur, Ojuela Mine.

Minerals from Mapimi
Minerals from Mapimi

Rosasite, Calcite, Hemimorphite, Mapimi
This was a really pretty and unusual specimen with Rosastite (turquoise blue), Calcite (flat colourless hexagonal disks on Rosasite) and Hemimorphite (elongate radiating clusters of whitish crystals), from Ojuela Mine.

Also in Mineral Zone's room was several Orpiment and Realgar specimens (both Sulphides of Arsenic) which Bill Shelton pointed out to me. These were found in 1959 and have been well looked after and kept in the dark to preserve the minerals. It is remarkable and rare to have the combination of both minerals, and it is thought to only occur at the Getchell Mine, Nevada, USA.

Orpiment and Realgar from Getchell Mine, Nevada
Colourful Orpiment and Realgar specimens from Getchell Mine, Nevada, USA

Opposite our booth was Mineral Masterpiece (Tom Spann and Irv Brown) - their first time exhibiting at this show. This room previously exhibited Stuart Wilensky Fine Minerals, and I caught Stuart catching up with Tom.

Stuart and Tom
Stuart Wilensky and Tom Spann

Tom had some great minerals including this rare Parisite, and an attractive Topaz on matrix.

Parisite from Muzo Mine, Colombia
Parisite on Calcite from Muzo Mine, Colombia

Topaz from Pakistan
Topaz from Shamozai, Katlang, Pakistan

In the room of Amazing Rocks and Minerals was this huge Calcite crystal, approximately 50cm high. It comes from the Cardin Mine, Picher, Oklahoma. This mine has been closed for 25 years, and I was told they evacuated the whole town due to Lead contamination. The Calcite was in superb shape considering it was found more than 25 years ago. The backlighting displayed the pink hue to the centre of the golden Calcite - this is caused by the trace element Neodymium.

Calcite from Cardin Mine
Calcite from Cardin Mine, Picher, Oklahoma, with pink centre caused by Neodymium. Crystal approx 50cm high, see pen for scale.

Mike Bergmann had a superb display this year partly due to several of his recent acquisitions. In mid July they discovered possibly the best pocket of Azurites at the Milpillas Mine, Mexico and Mike acquired the whole pocket. The Azurites are sharply formed with super bright lustre and crystals up to 4 by 4 inches! Mike was kind enough to show me this huge crystal.

Azurite from Milpillas Mine, Mexico
Azurite from Milpillas Mine, Mexico - 4 by 4 inches in size.

Mike had also recently acquired some fantastic Aquamarine crystals from the Frade Mine, Coronel Murta, Minas Gerais, Brazil. The Aquamarine crystals are huge, all between 8 and 12 inches in length, with a gem top - the best specimen had a gemmy top section of 4 inches. The crystals are all doubly terminated floaters, and showed evidence of terminating multiple time during growth. They also all had weird etching making for a very attractive and mineralogically interesting specimen.

Aquamarine from Brazil
New Aquamarine from Frade Mine, Coronel Murta, Minas Gerais, Brazil. Horizontal colour changes indicate previous terminations before the crystal continued to grow, and then later was etched.

Aquamarine, Frade Mine, Brazil
Another new Aquamarine.

Mike had also recently acquired an old collection of gem minerals, and they were really stunning - big crystals, superb colours, lots of old-timers that you rarely see coming out of mines now.

Gem Minerals from Mike Bergmann
Gorgeous Helidor crystal from Medina, Minas Gerais, Brazil over 10cm in height and two Brazilian Tourmalines to the right.

Tourmaline from Brazil
Gem blue Tourmaline from Brazil - one of the old-timer pieces.

Sally and Matthew Bergmann
Mike's lovely wife Sally and their son Matthew in front of their booth.

Fine Minerals International had one of the best displays in the show.

Fine Minerals International display
Display in the booth of Fine Minerals International.

They had some wonderful gem minerals including these Brazilian Tourmalines:

Tourmaline - Pederneira Mine, Brazil
Tourmaline from Pederneira Mine, Brazil with watermelon colouring.

Tourmaline - Pederneira Mine, Brazil
Another Pederneira Mine Tourmaline

Steve Perry (Steve Perry Gems) and John Veevaert (Trinity Minerals) had a booth filled with Benitoite and Neptunite specimens from the Benitoite Gem Mine in California. Both Steve and John have a lifelong passion for Benitoite. In the middle of this year, Steve and John worked a deal with Bryan Lees of The Collector's Edge to obtain 'the remaining few tons of everything he had related to the Benitoite Gem mine except for his gem rough production.' Bryan's operation (Benitoite Mine, Inc.) worked out 100% of the remaining in situ vein material at the mine betweeen 2000 and 2004. The mine site has now been rehabilitated, and the area has a closure order on it which prevents visitors looking through the colluvial material for specimens, so the specimens that John and Steve obtained are likely to be all that remains from the mine. They expect this supply to last 5 to 7 years whilst they take the time to prepare the specimens.

The mine is most well known for Benitoite and Neptunite specimens, but other minerals such as Joaquinite are also found. The minerals occur in white Natrolite veins or layers in a grey Crossite matrix. The veins are sitting in fractures in the matrix and where the veins cross you are more likely to find mineralisation. Steve and John had a range of material available from mine run (unetched) material (which was already sold out) to prepped specimens, and cut stones. Preparation of a specimen can take 15-20 hours of labour, and they are doing all the prep work themselves.

Mine run material
Steve holding a piece of 'mine run' - an unetched specimen showing the white Natrolite veins which may hold Benitoite.

Steve Perry
Steve holding a very large prepared specimen with many blue Benitoite crystals on white Natrolite.

When you start preparing a specimen it is a treasure hunt as you do not know what you will find within the Natrolite veins, but what you hope to find is one of the triply terminated Benitoite crystals which is triangular in shape. This specimen below started as a two fist sized boulder, John could see there was a triply terminated crystal in it, and kept sawing down to produce this great specimen.


The famous "Sushi" specimen of elongate black Neptunite, triply terminated blue Benitoite and reddish Joaquinite. This is in John's personal collection and he was very quick to add that it will definitely NOT become for sale!

The Stonetrust had a great display of Fluorites from Weisseck Mountain, Lungau, Salzburg, Austria. The recent Mineralogical Record has an article about this location and mining for the Fluorites (a challenging task!). I reported a find of  the Fluorites at the Ste Marie show earlier this year, with specimens seen in Watzl Mineral's booth. The Fluorites mostly have cubic form with stepped growth, and are quite dark colour until backlit.

New Fluorites from Weisseck Mountain, Lungau, Salzburg, Austria, on display in the booth of the Stonetrust

The specimens on display were from mining over the last ten years between 2000 and 2008.

But what I did not know until this show is that Fluorites exhibit an amazing colour change effect when lit by different types of lighting (such as tungsten light or daylight lighting). Stephanie and Robert Snyder were very helpful to show me the colour change with different lighting - the effect is very pronounced and I tried to capture the changes on my camera, however what the camera recorded was not quite the same as what the eye saw.

Fluorite over CREE LED light (2400 K colour temperature) - purplish on camera, but more purple and green to the eye

Fluorite over Mecury monochromatic light - this green is a pretty good representation of the green in real life.

Fluorite over compact Fluorescent light  (6500 K colour temperature) - teal blue

High Intensity Discharge LED, superbright light (5000K colour temperature - close to daylight) - deep blue similar to the Annabel Lee Mine blue Fluorites.

   If you would like to see a short video of the colour change please click here. Robert is moving the Fluorite over LEDs and the Compact Fluorescent light.

Robert Snyder kindly sent me some professional photos to show the colour change. These photos were taken by Anton Watzl, Snr.

Fluorite - pic courtesy of Anton Watzl Snr
Fluorite - photo by Anton Watzl Snr.

Fluorite - pic courtesy of Anton Watzl Snr
Fluorite - photo by Anton Watzl Snr.

Dave Bunk was exhibiting for the first time at the Denver Gem and Mineral show sharing a booth with Lithographie who produce the extraLapis magazines, and other books.

Dave Bunk
Dave Bunk at his booth

Dave also exhibits at the Holiday Inn, and to quickly return to that show, he had on display a whole case of minerals from El Mochito Mine, Honduras - not a common location for mineral specimens. Dave acquired the specimens about 2 years ago, and has recently prepared them for sale. The specimen come from a base metal and Silver mine, which is possibly the largest mine in Central America. The specimens were collected as they were found, but nothing has been produced recently. They are dominantly combinations of Galena, Sphalerite, Andradite, Calcite, Quartz and Silver.

Minerals from Honduras
Minerals from El Mochito Mine, Honduras

Sphalerite, Quartz, Andradite from Honduras
Sphalerite, Quartz, Andradite from El Mochito Mine, Honduras

Galena from El Mochito Mine
Galena with Quartz on Andradite from El Mochito Mine, Honduras

Calcite from El Mochito Mine, Honduras
A strange Calcite from El Mochito Mine, Honduras that had been attracting a lot of attention.

This show is great for teaching, and on opening morning school children come in to visit the show. Exhibitors are often on hand to explain minerals to the children - such as Paul and Penny from Wollongong University of Australia. Their display was on Australian Gypsum, and they were giving out free 'lucky dip' Gypsum specimens with labels to the children and explaining the inclusions in the Gypsum, as well as explaining the importance of labelling your collection - what a great way to encourage the next generation of collectors!

Paul and Penny from Wollongong
Paul and Penny from Wollongong University in front of their display.

I happened to walked past the Smithsonian Institution's exhibit whilst curator Mike Wise was there for their curator presentation. The Smithsonian has about 380,000 specimens in their collection, including minerals and gemstones, as well as a meteorite and rock collection. They have about 7 million visitors a year, and most visitors go to see the famous Hope Diamond, but end up looking at the rest of the exhibit. The exhibit represents only 2% of the collection. Much of the collection is a reference collection which is available to the scientific community for research.

Mike Wise from Smithsonian
Mike Wise from the Smithsonian in front of their display.

The theme of this year's show was the Creede Mining District, Colorado. One of the best displays was by Dave Bunk:

Creede Mining display
Creede Mining District minerals and old mining company share certificates.

Creede Mining District
Photo of the Creede Mining District above some displays

Creede Mining District display
Creede mining district display by Ed Raines

The Denver show is now over, and we are back home unpacking from the show. Denver is a very sociable and enjoyable show, and it has been wonderful to see everyone there. We look forward to next year's show!

Author: Robin
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