Event Report- 2014 Castro Valley Club-Newark Pavillion Show, Newark, CA (Feb 21-23)

A Visit to the Castro Valley Mineral Club Show, 2014

By Jeremy Zolan – Earth Surgery

The Mineral and Gem Society of Castro Valley puts on an excellent small mineral show each year at the Newark Pavillion in Newark, CA. This small locally focused show great for all audiences and ages, and makes for a wonderful weekend outing especially with family and friends! This show attracts dealers who offer an extremely wide array of material ranging from gem and lapidary rough to rare minerals. There are also many displays and booths offering activities, information, and many other things in addition to those who strictly sell specimens. During my visit, everyone at this show was extremely kind and made me feel welcome to the California collecting scene which I am extremely new to. For new residents of California looking to make connections, this is a great springboard into the scene.

I have recently been staying in the the Barstow area of Southern California so getting to this show was quite a drive. It did allow me a first glimpse at the landscape of many interesting places I have never visited before and was very scenic. Here we have a picture of high desert scrub in Boron, CA with the titanic US Borax Mine lurking barely visibly in the distance. Many of the hills in the photo are partially made from giant tailings piles. This mine is not only famous for its incredible size and high production but for its mineralogy which is highly distinctive. In addition to producing many thousands of fine colemanite specimens, it also is well known for splendid examples of many rare borates such as inyoite, kurnakovite, probertite, and kernite.

Scrub Desert on the way to a gem show in california

Scrub Desert on the way to a gem show in california

The first thing I did when I arrived at the show was check out the display cases, which there were many of for a small local event. In my home New England region, events of similar size only rarely have as many displays so I was pretty surprised. The cases were filled by a local crowd including both collectors and museums but definitely far more of the former rather than the latter. Lapidary, mineralogy, paleontology, and anthropological themes were all present in the displays however there was a significant bias towards the lapidary side of things with comparatively very few mineral display cases. This was somewhat reflected in the abundance of lapidary dealers at the show though there were also many great mineral and fossil dealers as well.

Morgan Hill Poppy Jasper on Display

Benitoite and Neptunite Specimens on Display

Cabochons on Display by Mark Montgomery at the 2014 Castro Valley Show

Fremont California in the Pleistocene Era

Specimen of Columbian Mammoth from San Francisco

Next off, I decided to parouse the dealer booths and was pleased with the great variety in not only species and localities but prices I saw. There were many great specimens to be had for under fifty dollars including many lots of old material at multiple dealers that appeared to have not been repriced in decades. There was truly something for everyone at this event.

The first dealer I visited was The Uncarved Block which always has a good assortment of material though tends to mostly focus on classic, well known species that display best in the thumbnail to cabinet range. Many specimens stuck out to me but those pictured below were my favorite, most of which are things that rarely turn up on the West Coast.

First off we have two teal kyanite crystals in a biotite schist matrix from the Harts Range in the Northern Territory, Australia. The color indicates that the specimen may more precisely be from Huckitta Well or nearby. The crystals were aesthetically skewered through the matrix and had a very pleasing deep aqua blue color. The longest was exposed to about 6cm of its total length. The Harts Range is one of only a very small assortment of localities in Australia that produce gem pegmatite minerals such as beryl and garnets.

Kyanite Crystals in Biotite Matrix from Australia

Next, I spotted this specimen of beryl from Slocum’s Quarry in East Hampton, Connecticut. This very uncommon, very old, and now very closed locality is well known for its yellow beryl var. heliodor crystals which were opaque to extremely gemmy and sometimes formed in pockets. The pocket crystals were often etched in a manner similar to the Ukranian crystals from Volodarsk-Volinskiithough their color saturation ranges to an extremely deep and gorgeous pumpkin orange color. Slocum’s Quarry also exhibits an impressive suite of rare Be, Nb/Ta, and REE minerals. Ernie Schlicter collected the below piece which has bigger crystals than most by far even though they are of a very light color for Slocum’s.

Beryl in Quartz from Slocum Quarry, East Hampton, Connecticut

Romanian amethyst from Porkura, Huneodoara Co. is something I am always looking out for and in my opinion, are some of the world’s great amethysts with their extremely deep color saturation and unusual crystal shapes. They strongly resemble newer specimens from Guerrero, Mexico but being the snob that I am, I think the Romanian specimens always have better color. I really loved this piece which has the perfect balance of purple cityscape-like crystals and contrasting matrix. Truly a fine amethyst.

Purple Amethyst Crystals from Romania

Finally, I spotted this set of alphabet agate from Indonesia. The letters are formed by natural tubular inclusions of iron oxides and clays in the agate. These sets always amaze me. Imagine how many thousands of pieces must be sorted through to get a full alphabet! Truly a daunting task, it has been said to take years to find a full set by inspecting rough. Some letters such as R and Q with unusual shapes are apparently rarer than others.

Agate Alphabet Cab Set

It was then over to Earth’s Treasures, run by avid field collector Rick Kennedy. Rick has been working the California Blue Mine in San Bernardino County for aquamarine, topaz, quartzes, wodginite, and other associated species. This locality is outside of what is traditionally regarded as the Southern California Pegmatite district so I had to know more considering it could change our perception of pegmatite mineralogy in California. It appears that this pegmatite is of intermediate elemental distribution (LCT/YNF) though it is likely very lithium poor unlike some geochemically similar envirtonments though the micas would need to be analyzed to truly validate that statement. Greisenization took place in the top of the peg and created a lot of topaz and fluorite mineralization while deeper in were the nice gemmy aquas. Some of the crystals show interesting tapering that reminds me of specimens from Brazil and Argentina. Below is my favorite crystal from the locality he had for sale at his booth.

Aquamarine from the California Blue Mine

Rick had lots of other great material too; a lot of exotics especially. This limonite after magnetite pseudo is very peculiar especially. Considering Kansas is mostly sedimentary, one would not expect to see magnetite originating from there. Many of these magnetites were collected around 100 years ago.

Limonite after Magnetite Psuedomorph from Kansas

John Garsow had a lot of great material too with a focus on gem minerals, rough, and materials. John is also an avid field collector who has made some really nice finds in Southern California. He had this Chinese tourmaline that immediately caught my attention. If there is one group of minerals that China lacks it is pegmatite minerals. There are only two very poorly explored main areas for specimen producing gem lithium pegmatites in China; near Kashi, Xinjiang Uygur Province or the Gaoligongshan ranges in Yunnan Province. Both are located in notoriously remote and culturally distinct regions in western China. This piece, measuring in at around 8cm tall is from the latter which is known for mostly producing only tiny crystals to 2 or 3cm. Chinese specimens show frequent mislabeling so it is possible this is from another entirely different area since it does not resemble the majority of specimens I’ve seen from either Xinjiang or Yunnan Provinces. I thought it was a really fascinating piece for that reason.

Gem Green Tourmaline from China

Taking a break from strictly minerals, I decided to check out the Northern California Geological Society’s booth to ask some questions about local geology since I am by no means well versed in the geology of California which is extremely different from those good old passive margins on the East Coast that I’ve explored and collected in so much. Mostly, I was curious about the formation, petrology, and mineralogy of blueschists and eclogites; rare, extremely high grade metamorphic rocks I was rewarded with kindness and a very thorough explanation. NCGS offers many excellent field trip publications exploring many themes in the northern California area. They also have an excellent scholarship program for B.S through Ph.D.-level students in California and the adjacent states.

Origin of Ophiolite and Franciscan Complexes

Geologic Cross Section of Mt. Diablo

Glaucophane Schist from the Franciscan Formation in Marin County

Alfredo Petrov has long been one of my favorite mineral dealers for the scientific focus of his merchandise. In addition to specimens of many truly weird minerals, he often has specimens of odd reagents or elements. He had several vials and containers of selenium, calcium, lithium, and samarium. I encourage the sale of element samples at mineral shows. Element collecting was quite popular a few years back but seems to have tapered slightly at least in the US. As for minerals, hw of course had a lot of oddball specimens..in fact too much to mention. Some of my favorites were his tiny sapphires panned from Japanese alluvial gravels, analcime and natrolite with celadonite from East Greenland- far away from the famous mineral producing regions on the frigid island. I thought one of the nicer high end pieces he had was this English torbernite. It is priced very competitively considering the quality of the specimen, high pedigree A.E. Foote label, and overall rarity of the material.

Torbernite from Cornwall, England

I have been a customer of Mineralogical Research Corporation (Minresco) in the past so it was great visiting their booth and looking through some of their flats in person. They had lots of fine quality, well known material from worldwide locations displayed in the front of the booth and rarer specimens behind. As for the material out front, I thought their specimens of the new azurite find from Lavrion, Greece were some of the better I have seen. I did however spend most of my time looking at the rare material in the back flats which was perhaps the most varied material in the entire show. I will refrain from mentioning my favorites because there were just simply too many. I did think this vial of szabelyite from Bou Azzer Morocco was pretty cool considering it was probably collected and studied far before the mine produced the specimens it is currently famous for. It may likely be one of the earliest collected mineral specimens from Morocco in circulation. That may not be saying much though considering that the vast majority of Moroccan pieces are no more than 20 years old. I still thought it was very interesting to see.

Szaibelyite from Bou Azzer, Morocco

Uranium Minerals for sale at the Mineral Show

The 2014 Castro Valley Show was great fun and it was definitely geared to a wider audience than I feel most smaller local mineral shows tend to target. Not only was there great diversity of material available, but amazing deals to be had. Not only is this a great show for everyone interested in minerals as a hobby, but would be rewarding for dealers looking to obtain inexpensive, high quality material for their inventory. As far as improvements, my only big criticisms were that I wish the displays had better labeling and there was more emphasis on local field collecting in them. I cannot say the show had any other drawbacks for me considering its nature and size. I thought it was awesome!!! This is a great event that I hope continues to be held for many years in the future!

Below is a specimen purchased at the Show which is available from Earth Surgery – Contact at JZolanSci@gmail.com to inquire.

Uranopilite- Happy Jack Mine, Utah Ex. Dr. Eugene B. Gross PRICE: $

Uranopilite Glowing under UV Light

Uranopilite- $100
(UO2)6(SO4)O2(OH)6·14H2O
Happy Jack Mine, White Canyon Dist., San Juan Co., UT
Ex. Dr. Eugene B. Gross
6.7 x 2.4cm 21.81g

email JZolanSci@gmail.com to order

The rare uranium secondary uranopilite is rarely available in specimens as rich as this one where it is present as bright highlighter-yellow powdery masses in a dark sedimentary matrix. The uranopilite masses may be poorly defined crystals. Typical of most uranyl minerals, the specimen is vividly fluorescent in all UV wavelengths and slightly radioactive. The identity of this specimen is highly credible- this specimen resided in the personal collection of Dr. Eugene B. Gross; a geochemist who prospected the uranium deposits of Utah for the Atomic Energy Commission.

Uranopilite has a very odd structure in that it is a polymer composed of metal oxo-clusters linked by sulfate “couplings.” This phenomenon of uranyl-clustering is observed in a select few uranyl species and have some structural characteristics of formal polyoxometallates, which of only one occurs in nature. If you wish to inform yourself more on the cluster chemistry of they uranyl cation, especially in minerals, I recommend this paper: http://minmag.geoscienceworld.org/content/75/1/1/F3.expansion.html

To search for minerals for sale that were mined in California, check out this search for minerals of California on eBay

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UV Light usage in mineral collecting – A Review of a dual band light under $100!

I finally got tired of not having a UV light to use in the field. Years ago I had a nice unit with dual LW/SW and a 12v cigar lighter plug, which worked with lots of portable battery packs and in my car for those nighttime visits to classic UV locations. Sadly, this light was lost and replacing it would be a few hundred dollars.

But, you never know how much you miss something like a good UV light until it is gone. There are just so many things a UV light helps with when checking out minerals. From the visual identification to seeing if a purchased specimen is glued, a good UV light pays for itself, quickly.

I was excited to read about the improvements to UVTools.com handheld Lamp, an all in one unit with a long wave bulb and a strong short wave bulb powered by 6 watts, a decent output, for just under $100. The kit comes with the light, which requires 3D batteries, a sample of minerals to test the light with shortwave and longwave reactive specimens. Safety goggles and a cd rom with study guides and informative literature complete the package, all in all, it gives a great start to any beginner, while the advanced collector will appreciate the power this highly portable hand held unit produces. I found the LW light to be very bright and it made some of the fluorites in my collection to glow bright white/blue. The shortwave light gives a bright reaction, but typically from a distance of no more than 6 inches from the lamp. It will not light up a hillside, or even a whole flat of minerals, but it is perfect for “one on one” specimen viewing.

Below: Photos of the kit, the minerals that came with it and some UV reaction from those specimens.

UV Kit, includes the lamp, 10 mineral specimens, safety glasses and a cd full of information.

UV Kit, includes the lamp, 10 mineral specimens, safety glasses and a cd full of information. Available from http://UVTools.com

Shortwave Photo Sample two Calcite rhombs glowing bright red

Shortwave Light Sample (photo taken with Galaxy S2 Phone)

Longwave Light Sample (photo taken with Galaxy S2 Phone)

Longwave Light Sample (photo taken with Galaxy S2 Phone)

You can purchase this UV Lamp from the manufacture, directly at http://www.ultraviolet-tools.com for $99.99.

There were two interesting things I learned by using this UV light. This agate deposit near my house became that much more interesting when I found out that every single piece of agate glows bright green under shortwave light. That means there is a lot of uranium in the area, which is giving the agate that color. Then, a hill over from that agate deposit, at another agate deposit, the brown crust on some of the agates was determined to be an uncommon variety of feldspar, after it was found that these crystals, in micron size, were glowing bright pink, typical of the species. You might wonder, so what, crusts of brown on agate? Well, the sweet thing is that these agates would now glow three different colors, green, pink and orange, sometimes yellow, as well. Three color rocks are what it is all about, so being able to notice the brown crusty bits on some of the agates helps identify them for further UV evaluation! It should be no surprise, those glowing agates include the local petrified palm root and what I like to call “Manix Lakebed Agate” which is a slurry of reeds, roots, rods and roughage from the lake that got silicated into a variety of translucent gel agate in shades of clear to black with red inclusions to a thick jasper-like layered wad of organics in stripes of black, red, cream and white. All of these organic masses were ripe with uranium! Several uranium deposits dot the mountains to the south, UV light is a great indicator of “hot rocks”!

At WhereToFindRocks.com we give this product our recommendation for best starter kit for novices and backup/handheld for advanced collectors.
Just under $100.00 from a manufacturer who stands behind their product. http://UVTools.com

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Big Diamonds to be Found at the Crater of Diamonds State Park

3.85 Diamond Found at Crater of Diamond State Park
It has been a productive year at the Crater of Diamonds State Park. To date, October 26th, 2013, nearly 400 diamonds have been found over the span of the year, with some rather large ones, several over 2 carats. For instance, Oklahoma teen Tana Clymer found a beautifully formed 3.85-carat canary diamond on October 19th, very similar to the fine diamond that was found by the late Marvin Culver, also of Oklahoma, in 2006. That diamond, the 4.21 carat “Okie Dokie Diamond” has been featured in several books, magazines and has been on display to the public a few times. Another large diamond, a 5.16 carat diamond was found by 12-year-old Michael Dettlaff of North Carolina in August. A 2 carat brown stone was found in June and all of these stones have one thing in common…

Many of these large diamonds are often found on the surface of the digging area.

One of the things many people are shocked to see upon arriving at the park is the actual mine area. It looks like a freshly plowed dirt field, waiting to be seeded and farmed. This area is poked and prodded, pitted and flipped, in search of the small gems distributed in the dirt.
Digging for Diamonds at the Crater of Diamonds State Park Field

Finding the park is very easy, once you are in the general area of Murfreesboro, Arkansas you will see signs pointing to the famous state park. You pay a nominal fee per person and go out into the field to search. You can dig, collect dirt and screen it, looking through the mud for a glassy pebble.
Digging for Diamonds at the Crater of Diamonds State Park

Or, you can do what many of the people who find the large diamonds do, simply walk around the dirt field, looking for crystals that have risen to the surface.
Digging for Diamonds at the Crater of Diamonds State Park

Either way, the Crater of Diamonds State Park is a great place to visit and try your luck at finding a precious stone. The chance of finding one of these stones is stacked against you, but if you happen across one of those rare 2+ carat stones, the Associated Press would like to acquire your photo posing with the stone.

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Rock Hounding for Agates in SouthWest Texas

Rock Hounding West Texas for Agate and many other great finds
By Erin Balzrette
for Katy Rock Shop
http://www.katyrockshop.com

Agate from South-Western Texas

Above: Banded Agate from the Alpine Texas area

After rock hounding in Texas with a guide as amazing as Frank Roberts of Austin, Texas, Dawn and I felt ready to go it alone. Also, we begged Frank to come if we got lost or could not identify what we were seeing, and he emailed us all weekend to be sure we were safe. Like I said, we “went it alone”, with Frank on stand-by. We grabbed a copy of The Gem Trails of Texas by Brad Lee Cross and decided to head out.

Agate from South-Western Texas

Above: Classic Agate from the Alpine Texas area

I called Paul at Moonlight Gemstone, of Marfa, TX, (432-729-4526) Bruce Huff, of Katy Rock Shop has a great respect for his beautiful work as do I, and I could not wait to see it for myself, and meet him. The Marfa agate is breathtaking. Paul Graybeal has exclusive rights to the private property in which most of Marfa agate is found. He explained that access to for us to do some hounding would not be possible. He keeps names or locations of land owners who place trust in him to protect their land from sought after agate to himself. It is easy to see why he protects the agate he does. It should be protected, and the land owners have the right to feel their trust has been in no way misplaced. Instead, he invited us to come see him work! This was an incredible offer that I was not about to miss! Paul is thoughtful, generous, patient and kind. I was as impressed by the man, as I was by the work he did, and the agate that surrounded us. Spending the afternoon watching him work, letting us work with him, learn from him, was and experience I will not forget.

Agate from Western Texas

Above: FIRE AGATE from the Alpine Texas area

We couldn’t wait to get to Woodward Ranch (WoodwardRanch.com) famous for the beautiful red plume agate only found there. There is so much more to find at the ranch! The Labradorite is a clear yellow! Opals that are gorgeous, and what she calls “yard art” is some of the most beautiful I have seen. (Yard art … no charge!) $6.00 a person, you are given a detailed map, a quick learner’s course, and shoos you before it gets too hot! When you return she counts it out, $6.00 a lb. for agate. We each left paying 18 dollars, 2 lbs. of agate, and many more lbs. of “yard art” so beautiful I am thrilled to have found it. A few items I collected from this trip are on my website. She was a delightful woman who spoke of her late husband Trey in a way that made you want to sit all day and talk to her. I, like so many others, are so grateful that Woodward Ranch is still operating and allowing others to see the wonder it has to offer.

Terri Smith of Alpine, TX, emailed to explain that she will set up Agate “Hunts” for you, a group, or family, in the fall. THE FALL when it’s….cooler? Terri is the logical one here. And so we will go back in the fall and go to the Ranches able to be hounded at that time on the tours given. The email was very nice and suggested that we try the book I had bought for the journey. I was grateful for the advice, and that I had picked the right book! I have heard only great things about Terri and her extensive knowledge of the area and experience.

“The Gem Trails of Texas Book” by Brad Lee Cross, was for our purposes to the mile, correct and accurate in its description of findings, and location. We found beautiful Jasper at the picnic table Jasper sight 8 miles from Marathon. Exactly as the book said. Amazon is one seller that carries the Gem Trails Series.

Agate from South-Western Texas

Above: Iron Rich Agate Geode from the Alpine Texas area

The West Texas Agate was a trip we will never forget, filled with beautiful surprises showing in each piece you see from that area. While visiting the Katy Rock Shop, you will see pieces from all over Needle Peak, Woodward, Marfa, and so much more and it is all there waiting to show you the beauty of West Texas.

Please find links to Katy Rock Shop, Terri Smith, Moonlight Gemstone, Woodward Ranch, Frank Roberts, and more at my website www.treeclimbersjewelry.com. Pieces I collected during this trip are displayed on the site as well.

Agate from South-Western Texas

Above: Iron Rich Carnelian Agate from the Alpine Texas area

Here at WhereToFindRocks.com we love using Hotels.com to find places to stay while out rockhounding!
And you never know when that hole in the ground is going to require working after hours on, so with Hotels.com,
No hotels.com Change or Cancel fees on lodging bookings!
So, find a hotel around Marfa, Texas or Alpine Texas and get out and collect some Agates!

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Collecting Tourmaline in Colorado – Brown Derby #1 Field Trip

The Brown Derby #1 Pegmatite, Gunnison County, Colorado- An unusual LCT-Type Pegmatite with Rubellite Tourmaline, Lepidolite and Rare Earth Element Species
Philip M. Persson
3139 Larimer St., Denver, CO, 80205
perssonrareminerals.com
Exploration Geologist

When it comes to Colorado pegmatite’s, most people think of the vivid and prolific smoky quartz and ‘Amazonite’ feldspar combinations or perhaps fluorite or topaz crystals from the Pike’s Peak batholith, which can be seen in collections all over the world. Tourmaline is certainly not a species that comes to most collector’s mind’s from the Rocky Mountains, yet Colorado does contain several unusual and interesting pegmatite’s of the ‘LCT’ (lithium-tantalim-Niobium) type which contain fairly high-quality (though not ‘gem’ in the pocket sense) tourmaline crystals along with other rarer species. The most notable and certainly the most studied of these deposits is the Brown Derby #1 Pegmatite, located in the Ohio City/Quartz Creek District, approximately 18 miles northeast of Gunnison in the high mountains of Central Colorado. First mentioned by Eckel (1933) and later by Staatz and Trites (1955) in their exhaustive study on the Quartz Creek Pegmatite District, this locality has long been of interest to both collectors and mineralogists. In recent years, however, due to a combination of property access issues, remoteness, and a shift in focus of Colorado collecting to ‘dig’ localities for smoky quartz, amazonite et cetera, the Brown Derby seems all but forgotten. This article is not an attempt to eclipse or duplicate the already extensive literature on this locality, but rather provide a modern and collector-oriented perspective on this fascinating deposit.

Quartz Creek Pegmatite District

Gunnison Colorado, where the Quartz Creek Pegmatite District is located


Quartz Creek Pegmatite District

Close up of the Quartz Creek Pegmatite District


Figure 1: Map showing location of Gunnison in Central Colorado (‘A’), with inset from Hanley et al. (1950) showing the Quartz Creek Pegmatite District, with the Brown Derby #1 Deposit marked with red star.

The Brown Derby #1 Pegmatite is the largest and most mineralogically-complex of a group of over 5 semi-parallel, dike-like pegmatite bodies which are situated on the western slope of a fairly prominent ~9400 foot high hill above the small settlement of Ohio City, approximately 18 miles northeast of Gunnison, Colorado, and 180 airline miles southwest of Denver. (Staatz & Trites 1955). According to Cerny (1991)’s pegmatite classification scheme, these are classic ‘LCT’ (lithium-tantalum-niobium) type deposits, and contain the geochemical and mineralogical characteristics of such deposits. They intrude ~1.7 billion year old metadiorite and associated metamorphic rocks of the Idaho Springs group, the Precambrian basement complex which covers a large portion of the State. Geochronology work by Heinrich (1967) and others found the pegmatite’s to be syngenetic to metamorphosis of the host rocks ~1.7 billion years ago, and they intruded as large sheet-like bodies parallel to the internal foliation and structure of the host rock. They strike N/NE and dip gently into the steep southeast hillside at 20-35 degrees (Heinrich 1967). The largest 3 pegmatite’s of the Brown Derby group all display exceptional mineralogical and geochemical zoning which is typical of most large LCT-type deposits, with the #1 Dike exhibiting the highest mineral diversity.

along the strike of the Brown Derby #1 Pegmatite
Figure 2: Looking Southeast along the strike of the Brown Derby #1 Pegmatite; large metal grate visible in center of photo is covering one of the underground drifts leading to a large stope on the core of the deposit. (Photo copyright Rudy Bolona/mindat.org)

Entrance to the #2 Tunnel, or main adit of the Brown Derby #1 Pegmatite
Figure 3: The Entrance to the #2 Tunnel, or main adit of the Brown Derby #1 Pegmatite, showing the sharp contact between pegmatite (white rock) and overlying metadiorite (dark gray) at the hanging wall contact. (Photo copyright Rudy Bolona/mindat.org)

The #1 Pegmatite was developed from the early 1930’s through the 1970’s and was mined principally for the lithium content of lepidolite, along ceramic-grade feldspar, minor beryl, and a somewhat substantial production of microlite, a tantlum species, though it is unclear if the resulting microlite concentrate was ever processed (Heinrich, 1967). It is presently divided into two properties in legal terms; a large surface exposure with associated dumps, which sit on National Forest/BLM land and are open to mineral collecting, and a fairly small underground portion which is owned by a group which identifies themselves as ‘Precious Offerings Mineral Exchange, LLC’ and is based in Boulder, Colorado. They are involved in Bureau of Mines-mandated remediation work on the underground workings of the Brown Derby #1 Mine, and as their willingness to allow collectors underground is not presently known. The author does not want to encourage activity which may compromise their remediation efforts; therefore this article will focus on specimens and species which can be collected from surface dumps and exposures, of which there are many. Hopefully in the future, the owners of the underground mineral rights will allow collectors to participate in their efforts to recover specimens from this unusual deposit.

The Brown Derby Mine is best approached from U.S Highway 50 from a small turnoff approximately 6 miles east of the small settlement of Parlin and 17 miles east of Gunnison. Turn north here onto Forest Service road 802, also locally marked as the 44 Road. From here, continue north ~1.5 miles, bearing right at the ‘Y’ onto 802 north where some small granitic-looking outcrops start to become visible on your right. Continue on this fairly good dirt road north/northeast past a small stream crossing (may not be passable to passenger cars after recent rain or in the spring) and ~1 mile after the stream crossing, bear left at another fork up an obvious large ‘humpback’ like sagebrush-covered hill, passing a cattle fence (please respect local ranchers and close gate after your drive through!). Continue on this steepening road for another ~1.5 miles over somewhat rough terrain (4 wheel drive/AWD necessary, though high clearance is not mandatory for this section) until you reach a large flat ridgeline with small aspen trees in a grove on your left. This is a good camping spot. Continue until the road apparently disappears into the sage rush, then pick up another fairly good dirt road leading steeply downhill to the left/west towards now fairly obvious white pegmatite mine dumps below you. Continue down past several switchbacks to an eventual right turn through an open gate to a mine access road leading past an abandoned shack where core samples were stored/examined. The large dumps below you and the large gated adit to your right are the Brown Derby #1 Mine.
Tourmaline: Tourmaline is found in an impressive range of colors and several species at the Brown Derby #1 Mine. Of primary interest to collectors are large crystals and sprays of Elbaite variety Rubellite, which ranges from a dull whiteish-yellow color to choice ‘hot pink’ crystals reminiscent of Transbaikal, Russia or Stewart Mine, California rubellite crystals in color. While generally not gemmy, rare crystals to several cm. are found frozen in lepidolite and cleavelandite matrix, which do show gemmy, clear sections that could potentially yield small gems. An early 1970’s Denver Post article reported gem-quality elbaite in small amounts from the Brown Derby Mine (Eckels 1997), but the author has not seen any of this material in collections or institutions. Most impressive and aesthetic are radiating ‘sprays’ of parallel to sub-parallel pink Rubellite crystals set in coarse purple lepidolite matrix, with individual rubellite crystals up to 15 cm. or more in length. Early reports indicate that in several ‘pods’ in the core of the pegmatite, ‘logs’ of elbaite tourmaine crystals up to 30 cm. long showing ‘watermelon’ zoning with rubellite surrounding an elbaite core were found. The author has personally seen well-formed crystals up to 20 x 5 cm. in place. Also interesting are elbaite crystals which are either partially or fully psuedomorphed by lepidolite or muscovite, which are locally common. Large masses of tightly intergrowth elbaite crystals showing an amazing color gradation from lime-green to yellow to pink to reddish within a single crystal were also found fairly commonly (Staatz & Trites 1955). Staatz et al. (1955) looked at the geochemical variations within these crystals as a guide to color and color gradation, as well at petrogenesis of the pegmatite as a whole. Schorl is also found fairly abundantly at the Brown Derby #1 Mine, where it occurs in the wallzone and outer intermediate zones of the pegmatite, generally in subhedral to poor crystals, sometime radiating outward into the metadiorite.

Rubellite tourmaline crystals in quartz
Figure 4: 4 cm. long, slightly gemmy hot-pink Rubellite tourmaline crystals in quartz with partial rubellite crystals surrounding it, Brown Derby #1 Pegmatite.

‘curved’ Rubellite tourmaline crystal in Cleavelandite
Figure 5: Naturally ‘curved’ Rubellite tourmaline crystal in Cleavelandite and lepidolite. Curvature resulted from tectonic movement in pegmatite during crystallization. Scale in cm.

radiating pink Rubellite crystals to ~5 cm
Figure 6: Spray of radiating pink Rubellite crystals to ~5 cm. in fine-grained lepidolite and quartz, similar to Stewart Mine, California material. ~15 cm. field of view.

‘polychrome’ tourmaline
Figure 7: Good example of massive to coarsely-crystalline ‘polychrome’ tourmaline with gradation from pink to green to yellow, showing some translucent to slightly gemmy sections. Field of View 15 cm. across.

Lepidolite: Second after tourmaline in interest to collectors, and arguably more famous from the Brown Derby Mine is Lepidolite, the violet-colored lithium mica, which occurs here as ‘books’ and crystals to over 10” across! Books of lepidolite several inches across are common, and even 6” crystals are not unusual. Masses of nearly solid lepidolite 5-10 feet across can be observed in places in the pegmatite. Lepidolite along with other mica’s at the Brown Derby Mine were studied by Heinrich (1967), who also noted muscovite, zinnwaldite, and polylithionite, though the occurrence of the latter is questionable. In addition to the large tabular hexagonal ‘books’, lepidolite also occurs as large masses of fine-grained, equigranular crystals to several mm., which generally host more unusual species such as microlite or monazite. Finally, an unusual variety known as ‘ball lepidolite’ occurs locally in hemispherical masses up to 15 cm. composed of rounded, subparellel crystals, which supposedly have been worked into cabachons and other lapidary items. All lepidolite from the Brown Derby #1 Mine shows a handsome rich purple color and a generally bright luster.

Lepidolite to 15 cm
Figure 8: Large books of Lepidolite to 15 cm. across in quartz-cleavelandite pegmatite, hand for scale.

Monazite-(Sm): In addition to fairly common mineral like elbaite and lepidolite, the Brown Derby #1 Mine is also unusual in it’s concentration of more unusual rare earth element (REE) species. Arguably the most interesting of these is the recent discovery of Monazite-(Sm), though the possibility of this species at the Brown Derby Was first noted over 50 years earlier by the always astute E.M Heinrich (1960), who analyzed several monazite samples from the Brown Derby #1 Mine containing >10% Samarium(!) Colorado field collector and REE specialist Rudy Bolona collected several specimens of brownish-red massive Monazite associated with white Cleavelandite feldspar and lepidolite from a single boulder on the dumps in 2009, and subsequently has a sample sent to Dr. George B. Morgan at the University of Oklahoma, who analyzed it to be the very rare species Monazite-(Sm), found only at 3 other localities worldwide. While all monazite samples from the Brown Derby #1 Mine analyzed by Heinrich (1960) appear to contain enough Sm to qualify as Monazite-(Sm), Monazite-(Ce) also occurs at this deposit, so it is not safe to assume that all monazite collected at the Brown Derby #1 is Monazite-(Sm). Monazite-(Sm) occurs at the Brown Derby #1 Pegmatite as subhedral masses to crude crystals up to ~6.5 cm. across, typically embedded in fine-grained lepidolite with cleavelandite feldspar and quartz. The Brown Derby #1 occurrence may represent the best locality in the world for this rare species, and new finds of this rare mineral are possible on the extensive dumps.

Monazite-(Sm)
Figure 9: Massive reddish-brown Monazite-(Sm) (analyzed) with purple lepidolite, 6.8 cm. across. (Photo copyright Rudy Bolona/mindat.org)

Pollucite: The Brown Derby #1 Pegmatite represents the only Colorado locality for this rare cesium species, which occurs as two large, ~30 cm. wide massive pods in the central core zone of the pegmatite, along with large crude crystals of opaque topaz, cleavelandite, and quartz (personal communication with Rudy Bolona, September 2009). No crystallized material is known, nor has this mineral been reported from the dumps.

Massive white crystalline Pollucite
Figure 10: Massive white crystalline Pollucite, 6.5 cm. across. (Photo copyright Rudy Bolona/mindat.org)

Stibiotantalite: Stibiotantalite is a rare Antimony Tantalum Niobium Oxide species found in LCT-type pegmatite’s and was first described from the Brown Derby #1 Pegmatite by Heinrich & Giardini in 1957. It occurs as subhedral to poorly euhedral crystals generally 1-2 cm. but rarely up to 5 cm. associated with the secondary Tantalum species Rynersonite as a white to cream surface alteration of the stibiotantalite. Heinrich & Giardini found stibiotantalite on a large boulder on the dumps of the #1 Pegmatite, and thought that possibly all the stibiotantalite in the #1 pegmatite was contained in this single block, a large mass of cleavelandite, topaz and lepidolite from the core margin core. However, recent finds of small Stibiotantalite crystals by Colorado collectors on the dumps would argue otherwise.

Well-formed 8 mm. long Stibiotantalite
Figure 11: Well-formed 8 mm. long Stibiotantalite crystal on lepidolite-cleavelandite pegmatite, collected recently on the dumps. (Photo copyright Rudy Bolona/mindat.org)

Columbite-(Fe): Columbite-(Fe), the Fe-analogue of the Niobium oxide species Columbite, is found in several assemblages at the Brown Derby #1 Pegmatite. In the core margin zone of the pegmatite, it is found with Cleavelandite feldspar, quartz, and mica minerals as large, crudely euhedral crystals to 10 cm. In the border zone of the pegmatite, especially towards the hanging wall contact with the metadiorite, it is found as small (<5 cm.) grains and crude crystals associated with reddish albite/perthite, Euxenite-(Y), and Monazite-(Ce). Nowhere at the Brown Derby deposit is Columbite-(Fe) an especially common nor conspicuous constituent, however it does occur through a wide portion of the pegmatite. Columbite-(Fe) in albite
Figure 12: Partial crude crystal of Columbite-(Fe) in albite, 8 x 6 cm. (Photo copyright Dean Allum/mindat.org)

Euxenite-(Y): A glassy green metamict Rare Earth species, previously identified as Betafite in some literature, is now believed to be Euxenite-(Y) (Heinrich 1967). Euxenite-(Y) is restricted in occurrence at the Brown Derby pegmatite to a core-margin albite replacement near the upper north margin of the core, but may exist in other unrecognized or mined-out zones as well. It occurs here as metamict masses to 4 cm. in weathered red albite with schorl and columbite-(Fe), and is highly radioactive.

Monazite-(Ce): Monazite-(Ce) occurs at the Brown Derby #1 pegmatite in several assemblages, making non-quantitative distinguishing from Monazite-(Sm) difficult to impossible. It is found as fairly sharp euhedral crystals to ~2.5 cm. in red albite with columbite-(Fe), probably from an analogous assemblage to the aforementioned Euxenite-(Y) zone. The Harvard University Mineralogical museum has several excellent crystallized specimens, one of which (HMM #104814) is pictured here.

Monazite-(Ce) to 2.4 cm. in perthite-albite-biotite pegmatite, Harvard Mineralogical Museum
Figure 13: Well-formed crystals of Monazite-(Ce) to 2.4 cm. in perthite-albite-biotite pegmatite, Harvard Mineralogical Museum #104814.

Microlite: Microlite, the complex tantalum oxide species, is known from several zones of the Brown Derby #1 Pegmatite and was one of the significant economic minerals of this deposit, though the present distribution of microlite in the dumps and in-situ would suggest otherwise. This is probably due to the fact that microlite occurred in concentrated ‘shoots’ or elongated pods in fine-grained lepidolite-quartz-cleavelandite pegmatite, a mode of occurrence similar to that at the famous Harding Pegmatite in New Mexico. These ‘shoots’ were mined selectively for their microlite content, and ~1200 pounds of Microlite was concentrated and stockpiled for processing, though it is unclear if this material was ever actually sold (Hanley 1950). Hanley also estimates that ~9,000 lbs. of microlite remained at the time of his study in 1944 at the Brown Derby #1, though it is unclear how much of that has been mined since. Mineralogically, microlite forms small crude to somewhat euhedral octahedral crystals to 1 cm. with a resinous brown to black luster and distinctive radiation ‘burn halo’s’ in the surrounding lepidolite. These crystals are often quite radioactive and may in fact be uranomicrolite.

Microlite in crude 3-4 mm. crystals in fine-grained purple Lepidolite
Figure 14: Microlite in crude 3-4 mm. crystals in fine-grained purple Lepidolite; specimen 4 cm. across. (Photo copyright John Betts/mindat.org)

Other accessory species: For the sake of brevity as well as the fact that they do not occur in ‘collector-quality’ crystals, other species such as Topaz, Beryl, Garnet, and Bismutite will not be discussed in detail here. Suffice it to say that they are present at the Brown Derby #1 Pegmatite, and a quick search of the already extensive literature on this deposit will yield many interesting references.

In closing, the Brown Derby #1 Pegmatite remains one of the more interesting and unusual pegmatite deposits in Colorado, and unlike many similar localities, a large portion of the dumps as well as surrounding prospects remain both on public land as well being as accessible to vehicles. The Brown Derby #1 deposit is also unusual in that while it continues to yield excellent, aesthetic specimens of relatively common minerals such as Rubellite tourmaline and lepidolite, finds of extremely rare species such as Monazite-(Sm) have also been made recently. If you plan to visit from Brown Derby #1 Pegmatite, please be respectful of local claim holders and property owners and exercise safety and common sense around the large dumps and potentially dangerous mine faces and outcrops. With persistence and luck, this locality should continue to yield great mineral specimens for many years to come.

References
1.) ‘Mica’s of the Brown Derby Pegmatites, Gunnison County, Colorado’, Heinrich, E.M, The American Mineralogist, Volume 52, July-August 1962.
2.) ‘A New Lepidolite Deposit in Colorado’, Eckel, F.B., American Scientific Society, 16, pp. 239-245.
3.) ‘Lithia Pegmatites of the Brown Derby Mine, Gunnison County Colorado’, Hanley, John B., 1946, American Mineralogist 31, 147.
4.) ‘Pegmatite Investigations in Colorado, Wyoming and Utah: 1942-1944’, E.M Heinrich et al., USGS Professional Paper Paper 227, 1950.
5.) ‘Stibiotantalite from the Brown Derby #1 Pegmatite, Colorado’, Heinrich, E.M & Giardini, A.A., American Mineralogist 45, pp. 728-731, 1960.
6.) ‘The Quartz Creek Pegmatite District, Gunnison County, Colorado’, Staatz, M.H. & Trites, A.F., USGS Professional Paper 265, 1955.
7.) ‘Paragenesis of the Topaz-Bearing Portion of the Brown Derby #1 Pegmatite, Gunnison County Colorado’, Rosenberg, P.E., American Mineralogist 57, 571-583, 1972.
8.) Mindat.org, accessed 8-01-2013 to 8-15-2013.

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