LAZULITE: TUCSON GEM SHOW: MAIN SHOW

In attending the Tucson “main show” I remained on a hunt for the best $5 mineral I could find at the venue.  Now, there are very few $5 minerals for sale in the Convention Center but there are numerous five figure minerals a buyer could take home!  But, the hunt is the fun part of the chase and I brought home some nice crystals of lazulite a magnesium, iron, aluminum phosphate [(Mg,Fe⁺⁺)Al₂(PO₄)₂(OH)₂].  Lazulite is often a sky-blue to azure-blue color but my crystals are such a very deep blue or blackish-blue that the camera will not pick up such---as is the case for crystals collected at the well-known Rapid Creek locality in the Yukon, Canada. Crystals from Rapid Creek are stubby bipyramids, have a vitreous luster and are transparent to translucent.  On the Rapid Creek crystals a strong light will transmit through the specimens and produce the beautiful blue color.  Crystals are fairly hard at 5.5-6.0 (Mohs).

 

Bi-pyramidal crystals of deep blue to black-blue lazulite (L) and quartz (Q) collected from Rapid Creek, Yukon Territory, Canada. Width of specimen ~1.75 cm.

Luzulite is found in high grade metamorphic rocks where it is associated with kyanite, corundum, andalusite and others.  It also may be found in some massive hydrothermal pegmatites. The magnesium-rich lazulite is in a solid solution series with the iron end member scorzalite [(Fe⁺⁺,Mg)Al₂(OH,PO₄)₂].

Two photomicrographs picking up the dark blue color of lazulite crystals, each has a maximum width of ~ 3 mm.  Also present are tiny terminated quartz crystals.

It is easy to confuse lazulite with lazurite, a blue variety of the mineral Hauyne, a sodium-calcium tectosilicate with sulfur, sulfate and chloride.  Lazurite is found associated with pyrite in zones of contact metamorphism of limestone and is the major “blue” component of lapis lazuli (a mixture of lazurite, pyrite, calcite). 

In my hunt for the best $5 mineral at the different show venues, I sought advice from a friendly Arizona rattlesnake:

·       Be flexible

·       Keep a low profile

·       Think before you strike

·       Soak up some sun

·       Shed your old ways

·       Be thick skinned

·       Don’t get rattled

TUCSON GEM SHOW: 2015 MAIN SHOW

Today, February 12, was the opening day of the 61^st Tucson Gem & Mineral Show---the “main show”---held at the Tucson Convention Center.  The show theme for 2015, Minerals of Western Europe, brought a number of exhibitions featuring fine minerals from a variety of localities, as well as European dealers and their wares.  The following photos represent only a small portion of the many minerals in display exhibitions and dealer cases.

A Native American "Spirit Doll" with gemstone adornments.

Bowl: Brazilian agate, ca. 1970, Idar-Oberstein, Germany.

A great pyromorphite from the Las Ferges Mine, France.

A variety of specimens from localities in western Europe.

Great Norwegian silver from the famous Kongsburg District.

More silver from Kongsburg.

Mimetite from the Cumbria District, England.

Sulfur crystal from Sicily.

The star of the Show: topaz collected by Rich Fretterd (as seen on The Prospectors TV show) from pegmatites around Pike Peak.  The stone on the left is a piece of 1345.25 ct. billed as the largest faceted topaz from the USA.

More topaz from the Pikes Peak pegmatites.  For a great story, and many photos, of the topaz see www.spiriferminerals.com.

There is always gold at the Tucson Show.  This is the eight pound Thunderbolt collected from western Australia.

Beautiful rhodochrosite and fluorite from China.

Come to Arizona and see Bisbee azurite!

 

Brazilian amethyst and calcite in above three photos.  Spectacular.

The geode crackers are always popular.

I spent most of Thursday at the show and was simply overwhelmed, as usual, with the many cases and specimens.

PARGASITE: TUCSON GEMS SHOW REPORTS: WHOLESALE

The big event of the day was traveling south to the wholesale shows in south Tucson.  Most venues seem clustered around the Holiday Inn and the Kino Shows and are in the extra-large “tents.” Inside each tent the numbers of booths and tables are almost overwhelming.  Vendors are selling a wide variety of jewelry, beads, rings, cabs—you name it.  We toured through several of the tents and the displays seemed identical.  I could almost believe that the different rings etc. were all manufactured in the same factory.  I also could not observe prices that appeared to be “wholesale” in nature.  Most of the gems, cabs, silver pieces had lower prices at other venues scattered around town--or so it seemed.  So, off we went to one of my favorite shows, the 22^nd St. venue. 

 

Lots of beads.

Silver of all sorts, shapes and prices.  A great variety of chains.

From semi-precious to the big boys: rubies, diamonds, sapphires, tanzanite, etc.

Rings for everyone.  Amethyst and red garnets seemed a good buy.

I wandered through the displays back to the table featuring Pakistani minerals where previously I had purchased ruby and spinel.  I had remembered the dealer also had a green mineral for sale that was nicely perched on a white marble—similar to the ruby and spinel.  However, I would need my best negotiating skills since this green mineral was originally priced at over my $5 minimum!

I was able to purchase the mineral, pargasite, a sodium, calcium, magnesium, aluminum silicate that is a member of the amphibole/hornblende group.  The chemical formula is one that would confuse a beginning mineralogy student: [NaCa₂(Mg₄Al)Al₂Si₆O₂₂(OH)₂].  As I understand the situation, pargasite is not only a mineral but part of a “group” bearing its name. Chromio-pargasite has chromium substituting for the aluminum; in ferro-pargasite iron replaces the magnesium, fluoro-pargasite has fluorine replacing the part of hydroxyl radical, potassic-pargasite has potassium replacing the sodium. 

 

I really liked this electric green variety of pargasite from Pakistan.  The translucent specimens are fairly expensive but like the previously purchased ruby and spinel, parasgite is a colorful metamorphic mineral perched on the snow white marble.  Length pargasite ~1.0 cm.

Like most hornblende group minerals pargasite occurs as opaque, dark green to green brown, prismatic to columnar crystals with a hardness of 5-6 (Mohs).  It has a vitreous to subvitreous luster and the prismatic forms have that diamond shape cross section created by cleavage angles of ~56^o and ~124^o. 

However, there is a variety of pargasite that is an electric green color and gemmy and transparent and that is what I purchased.  This type of crystal stands out very nicely on white marble.  The specimen came from the Hunza Valley of Pakistan and was found in metamorphosed carbonate shelf limestones.