What's New for Denver 2012
Its Denver time already again and soon we will be on our way to the second largest gem and mineral show in the United States. We will be open for business starting Sunday, September the 9th at 10:00 AM. In past years we have sometimes allowed customers to prowl through our merchandicde during our set up inspite of the inconvenience it causes us to permit this. This year we will have a firm policy regarding this and will be completely closed during our set up. In addition we are working with the show promoter, Martin Zinn to make sure that all of the outside venders are able to start selling at the same time. We hope you will understand why we are doing this.
So why should our customers want to inspect our merchandice before the official opening. Well, they want to have first crack at the new things we are bringing to the show. Each year we go to substantial effort to try and find new and interesting things for our customers and this show is no exception. We have been fortunate to purchace a very large lot of old material from a manufacturing jeweler in the Los Angeles area and it contains a great deal of gem and cutting rough that he accumulated over the past 50 years in business. He is now quite old and complains that the weather in the Los Angles area is too cold and that he wants to move to Hawaii!!.
From this source we acquirred about 1500 pounds of good quality natural Turquoise, much of it from Kingman, Arizona as well as some from Baja, California. It is not chalk, or at least most of it isn't. We have been able to process only a part of this hoard and will undoubtedly be selling this material for several years. In addition, we also bought from this source a large quantity of red precious coral from the South China sea which he bought in Japan many years ago. Much of it is quite red or dark pink. Again we will be able to prepare only a fraction of this material for the show. Also a cart load of flats full of old mineral specimens from various places.
Also from this hoard we will offer a number of flats of rough pieces of fairly gemmy Aquamarine, Morgtanite and Beryl. There will be bags of tumble polished gem gravels from Burma that was imported into this country more than 30 years ago. It is quite small, but is almost all Spinel, Sapphire, Ruby and other colorful grains. I am not sure what might be done with this material, but it is true gem gravel that was picked out piece by piece by ladies who picked out of the gem concentrates grain by grain. There must have been several man years of labor involved in picking out all these tiny stones.
There are some flaqs of gemmy Amethyst suitable for faceting. Many small cabochons of fine quality Chrysophrase, some chunks of gemmy yellow Sphalerite from Spain. Some interesting Malachite and Azurite from Baker, California of all places that cuts pretty blue and green stones. A number of flats of Rutile in Quartz with heavy golden Rutile. Some flats of gemmy yellow Apatite crystals from Cerro de Mercado, Chihuahua, Mexico. Quite a few little bags of gemmy Amethyst, Garnets, Citrine, Peridot and Tourmaline and some others.
A few years ago we operated a Quartz mine in Minas Gerais that produced fine Quartz phantoms. We got a couple of flats of these that we will be bringing to the show. A couple of flats of rough blue Sapphires and Rubies from Africa. These won't be breaking any records for value, but they are not bad. There will be some Tektites from Thailand, China and Columbia. Some interesting blue Chalcedony from Namibia. A couple of flats of Varisite from Lucien, Utah. Tumbled stones, cabs and tiny tumbled gems: Amethyst, Citrine, Peridot, pink Tourmaline, green Tourmaline, Chrysoprase cabs, Moonstone cabs, misc. cabs
Just before the show we got in a shipment of four to six inch plates of high quality Amethyst crystals from Uruguay and hearts made form the same quality Amethyst. A nice lot of what we call Amethyst eyes from Uruguay. Also new shipments of Quartz crystals from Collier Creek, Arkansas, polished golden optical Calcite, Chrysanthemum stones, China, fibrous and polished Malachite, D.R. Congo, Aqua Aura coated Quartz crystals, cactus Quartz and clusters Orange Aura coated Quartz crystals and cactus Quartz etc. There will be a nice lot of sulfur specimens from a pallet of specimens we discovered on our pallet racks.
There will be a lot of other stuff including our usual cut and polished Fluorite items and other items that we usually have. We hope the above will be enough new stuff that you will want to come and give us a look.
Turquoise rough from Kingman, Arizona, USA
Turquoise has been defined by the International Mineralogical Association as a triclinic copper phosphate.
Cu(Al,Fe+3)6(PO4)4(OH)8·4H2O.
For years turquoise, was a real mineralogical mess and often any blue rock or mineral was likely to be called turquoise. It had not been studied very much. Often turquoise was a mixture of minerals and the mixture varied depending on which locality it was from. Finally Dr. Eugene Ford of the United States Geological Survey did a study on the stuff. His first job to find some pure turquoise, preferably in the form of crystals from which he could do a structural analysis of turquoise. He chose for his work the microscopic but quite perfect crystals of turquoise from the Lynch Station Prospect, Campbell Co. Virginia, USA. He used this as a standard turquoise in his analysis of other blue minerals and rocks that had been labeled turquoise. He discovered that many stones called turquoise were other members or mixtures of the turquoise group of minerals like chalcosiderite, faustite, aheylite and planerite with which it forms a solid solution series. Many other rocks containing other blue minerals, frequently copper minerals like chrysocolla have also been given the name chrysocolla. The fact remains that most people in the world really don't know the difference between a rock and a mineral and the names they often give rocks and minerals often has little relationship to our current scientific understanding of them.
Classically, turquoise came from Iran near the town of Mashad not far from Turkmenistan and Afghanistan. For more than 1000 years this was the locality for the best turquoise. The Indians in Arizona and New Mexico had mined turquoise for ornamental purposes for a long time and it attracted the attention of white settlers and miners when they came from the eastern part of the United States in response to the gold, silver and copper in the western states. Back then, many blue rocks were called turquoise. Often the way that the quality of turquoise for jewelry purposes was determined, was to put your tongue on the rock. Low grade turquoise is frequently porous and it wicks up the saliva on your tongue, causing the rock to stick to your tongue, sometimes painfully so. This is a good quick way way to determine the porosity of a stone, and I have used this trick on many occasions. Making the stone wet will also allow you to more closely estimate how the stone or mineral will look after cutting and polishing. This is why rock hounds and lapidaries (those who cut and polish rocks) have on occasion been called rock lickers.
Much of the turquoise we offer is from the Kingman, Arizona area and is from an old hoard of the stuff that had been bought and stashed away back in the 60s and 70s. So now it has come out of hiding and we can offer it to our customers at what we think are reasonable prices. We are continuously asked for turquoise by our customers, but we often do not often have it in stock. We used to get some “chalk” turquoise from Mexico, but our source of that material dried up long ago.
If you want to look up Dr. Eugene Foord's article on Turquoise, please consult the Mineralogical Magazine (a professional British publication), February 1998, v.62, no1, p93-111.
Available in various sizes and qualities.
Rutilated Quartz rough from Ibitiara, Bahia, Brazil
Rutile in Quartz, Ibitiara in Bahia state, Brazil.
The material we have is not of outstanding quality compared to the glory days of Rutile in Quartz in Bahia, Brazil, but many of the pieces are pretty good and I have not seen any of this material on the market for a number of years and suspect that, like so many things we have sold over the years, it will "evaporate" and we will wonder where in the world it all went.
The best specimens of Rutile in Quartz come from near the little town of Ibitiara in Bahia state, Brazil. Hundreds of tons of material has been mined at this locality. These are pieces and crystals of transparent quartz that have included in them laths and 'spears" of golden Rutile. Most Rutile crystals are black, but sometimes when it gets thin it can be seen to be a deep red color and when it gets very thin, like at this locality, it becomes golden. Back in the 60s, this material was common as dirt. I remember one of the big lapidary dealers in Glendale, California was offering wooden boxes, each of which had 50 pounds of good Rutile in Quartz rough for less than $100 per box. Today you would have to pay at least $50 a pound for similar material right at the locality, and you would have to fight off the resident Chinese stone buyers for the privilege to do so. Now, little of this material finds its way into the hands of the local Brazilian cutters.
Back in the 1980s I made several trips to this locality in Bahia (heart land Brazil), to buy Rutile in Quartz. Even then it was expensive, sometimes breathtakingly so and although I was able to buy some material, I had to leave the best of it behind because they wanted thousands of dollars, even back then, for the best of it. The best of it consisted of big "stars" of golden Rutile growing inside of clear Quartz. Sometimes these stars reached three to four inches across. Actually they were "spears" of golden Rutile epitaxially oriented on hematite crystals inside the quartz. As a specimen collector I was always looking for good shiny undamaged crystals of clear quartz with good heavy golden Rutile inside. These were always very difficult to find. In a lot of say, 100 kgs of Rutile in Quartz rough you might find two or three fairly well formed quartz crystals with good heavy golden Rutile inclusions, but most of the time they all had some damage. I finally gave up going to the locality, because it was a long trip to get there and I never got very much there. Often the rough from this locality would find its way down to Governador Valadares in Minas Gerais state, Brazil, and much of it was cut into faceted stones and cabochons which you could buy by the Kg at ten cents a carat. I would sort through various lots trying to buy the few specimens of well formed quartz crystals with good Rutile inclusions. I never found one really good one. The two fine examples I finally got for my collection were both bought in Belo Horizonte at pretty hefty prices. I just shut up and paid the money because the price was starting to go up dramatically because of the interest of the Japanese, Taiwanese and the Chinese in this material.
Calcite rhombohedral cleavages: Iceland Spar
We sell natural semi transparent natural rhombohedral cleavages of calcite from Mexico as well as a higher quality variety of polished cleavages from Bolivia.
Natural Calcite cleavages from Mexico:
Our Mexican calcite cleavages range from fairly clear to slightly clear in parts. They are completely natural except that they have been broken from larger natural calcite crystals.
Polished Calcite cleavages from Bolivia:
These are of a substantially higher quality than our Mexican material. It is usually much more transparent and the cleavages have been polished on their surface. Even though they are more expensive, they have proved popular with our customers.
Calcite var. Iceland Spar.
Iceland spar is just calcite that is clear enough to show the property of double refraction. In practical terms this means that when you view a line or print through the calcite, its optical properties will make the line or print appear to be doubled. This is due to double refraction where the incoming light is broken into two separate components and reflected back out of the stone as two separate images. Double refraction is common in many minerals, but it is very pronounced in calcite and calcite is the most commonly available mineral that can be used to demonstrate this.
Calcite is one of the most abundant minerals found in the earths crust and there are thousands of localities where calcite can be found. A few of these localities produce Calcite crystals that are well formed and transparent. This variety of calcite has historically been called Iceland Spar. The reason for this is that in Iceland, in the 19th century giant crystals of calcite up to 7 meters were found. This deposit produced abundant material and gave this variety of calcite its name. This deposit has long been exhausted and no Calcite crystals have ever been found that were larger. A small percentage of these crystals were of transparent calcite. When these crystals were broken up to collect and ship them, they would commonly break into rhombohedral cleavage sections typical of calcite from any locality.
This ability of calcite and other minerals to break continually into smaller and smaller identically shaped cleavage pieces is one of the things that got scientists thinking about how small could you break them and that there must be some very small size beyond which you could not break/cleave them any smaller. This lead to the unit cell theory of mineralogy at an atomic level. Calcite also has the property of double refraction where light entering a crystal is split into two polarized light rays and this property is very pronounced in Calcite and is demonstrated by it, perhaps better than any other mineral. When you look through a piece of calcite at a line or a line of text on paper below it, the line or line of print appears toe be doubled.
These two properties, its cleavage and its double refraction make it eternally popular with earth science instructors to illustrate two common fundamental properties of many minerals. The more transparent the calcite the more expensive it is. Pieces of completely transparent calcite in large sizes (larger 200 grams) are in high demand for optical devices and can bring several more than 1000 dollars a kilogram in larger sizes. That is why we do not have any completely transparent calcite to sell.
Historically the best and most abundant source of this clear calcite was in Iceland and therefore gave it its name of Iceland spar. However there are very many localities for calcite that is clear enough to demonstrate this property and today probably the most abundant material comes from Mexico. Almost all the calcite that is used to demonstrate the doubly refractive properties of calcite are in the form of cleavage rhombohedrons, examples of which are pictured below. They are frequently only clear enough so that you can demonstrate the doubling property, but not completely transparent. The completely transparent and untwined variety that are in demand for optical instruments can cost more than $1000 per kg.
Our rhombohedrons of calcite/Iceland spar are ideal for demonstrating double refraction and for showing the classical rhombohedral shape. We carry two qualities of this material. The cleavage rhombohedrons from Mexico are of a lower grade and are less expensive, but we also have higher quality cleavage rhombs from Bolivia that has been polished in Brazil.