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Cal-Portland Rillito Quarry – TGMS Field Trip - May 11, 2019


Twenty-two members attended the May 11, 2019 TGMS Field Trip to the Cal-Portland Rillito Cement Quarry.  Just off of Twin Peaks Road, a few miles west of I-10, the quarry produces the raw materials for Cal-Portland’s Portland Cement plant about five miles north of north of the quarry off I-10. 

Quarry Manager, Jared Stokes graciously hosted us, describing the general geology of the deposit, the rock units mined for various grades of cement, and the process used to grind and mix the recipes to produce cement with different specifications.  He also explained that we were standing in the hole created by the removal of one of the Twin Peaks, for which the Road and an Elementary School were named.  Mining had begun there in the 1940s.  Besides being a great host, Jared was very interested in any insights we could provide about the geology and mineralogy of the rocks.


The nature of cement quarrying requires very consistent rock properties and composition, which, in general, is not promising for a mineral collecting trip.  Recognizing that, Jared took us to a portion of the quarry where the rock is much more variable, broken by numerous veins and intruded by igneous dikes.  Prior to the trip, he had his equipment operators pull numerous piles of the various rock types out onto the bench, to make them more safely accessible.  This and the fact that we were the only ones in the quarry that day, we were free to wear comfortable shade hats rather than hard hats.  (As he pointed out in his safety lecture, the greatest hazard that day was the sun!)

Members collected a number of interesting specimens, including small water-clear calcite crystals with limonite-goethite inclusions, nice manganese dendrite specimens, a dense caliche-cemented breccia, and distinctly pink calcite vein pieces.  Everyone drooled over a large boulder of the material, out of reach on the bench slope above us.  A few small fluorite crystals were collected, but none of the banded fluorite collected on a previous trip. 

One of the attached pictures shows pink calcite veins, crosscut by later white calcite.  A second picture shows a spectacular manganese dendrite, more than two feet “tall”.  While no-one probably found anything that will win a “best of show” trophy, it was an enjoyable and easy trip, made all the better by the nice weather and the gracious hospitality of Cal-Portland.

Article/photographs by Mark Marikos and Ron Gibbs

TGMS "Family Fun Day!"


Saturday, October 13, 2018, TGMS held its second TGMS Family Fun Day.

Living in Arizona, a rainy day is usually something that we don’t worry about; actually, something we are delighted to see. But leading up to that Saturday, the TV weather announcer kept upping the percentage of rain. Most of the time they come close but this Saturday, they were right!! Once it started to rain it rained ALL DAY!!


Being rockhounds, we are all pretty much optimistic. Because when we go out collecting, we are sure that we are going to find something spectacular. But on this very rainy day, our optimism wasn’t that high … but of all the events that where going on in the City of Tucson that weekend … OURS was inside. That is like having an “ace in the hole.”

At 9:57 a.m. we had our first participants through the door … Danelle and Jaden Arturet. They braved the rainy weather and came to our TGMS Family Fun Day! Because Jaden was our first child (literally) through the door, she got to pick out a very special mineral specimen for herself … it was a really nice quartz crystal. Thank you both for coming!


Everyone through the door was greeted with a smile, then handed a “mineral passport” card, plus a raffle ticket (for hourly TGMS Membership giveaway). The “mineral passport” cards where stamped by each station that a child stopped and visited with. They had lots to see! The different stations were; fossils, micros, meteorites, rock and mineral identification, fluorescent mineral display, walk through a cave, rock dig, hourly giveaways, rock identification, a coloring contest, and personalize a bracelet.


After taking an earth science trip around the room, they got to go to the “spin the wheel and win a prize!” We had mineral specimens, hats, gold pans, 10x eye loops, lanyards, bags, and a host of other fun things to choose from. It was fun listening to hoots and hollers when the “wheel” landed on a “TGMS Gold Seal.” That’s when they got to choose their OWN very special mineral specimen.

We had over 250 people participate. There were parents, grandparents and children that came to visit us on that fun and rainy day. We feel that we had a pretty successful event. We received lots of “Thank You’s”, donations to the cause and we even sold a few TGMS products. By all accounts … it was a SUCCESS! AND we all had fun!

A big “THANK YOU” goes out to: Tim McClain, Ron Gibbs, Mark Ascher, Brad Gibbs, Victoria Fila, Rose Marques, Kerry Towe, Mike Hollonbeck, Diane Braswell, Mary Kirpes, Kent Stauffer, Linda Stauffer, Daniel Kirpes, Christine Marikos, Mark Marikos, Ortrud Schuh, Louis Pilll, Bob Melzer, Bill Shelton, Myles Isbell, Jennifer Isbell, Dick Gottfried, Linda Oliver, Bre Oliver, Trey Oliver, Kyleigh Oliver, Cailen Oliver, Molly Radwany, Beverly Lynch, Susanne Collier, Marilyn Reynolds, Bruce Kaufman, Warren Lazar, Cathy Logan, Pat McClain.

So onward and upward to our next community outreach program and, hopefully, we will do this very special event again!

Wulfenite Is Loved

"WULFENITE IS LOVED" … Our 2019 Tucson Gem and Mineral Show® Theme 

By Peter Megaw, TGMS Exhibits Chair

Wulfenite (PbMoO4) is as Arizonan as Saguaros, Gila Monsters and Snowbirds…and in 2017 was officially recognized by our Legislature as our Official State Mineral.  This puts it in company with Petrified Wood as our state fossil, Turquoise as our state gemstone, the Bolo Tie as our state neckwear and Copper as our state metal.  In one way or another all these “official state” designations are an outgrowth of our hobby and Show and reflect the maturing of tastes…with mineral specimens finally getting the recognition they deserve! 


 So why “Wulfenite is Loved”?  The answer goes back to the late 60s when some (presumably successful) mineral collector scrawled PbMoO4 is LOVE (no “D”) on an old shed at the Red Cloud Mine…arguably the world’s finest wulfenite locality.  Photographs of this graffito appeared in the mineral collecting magazines and spawned bumper stickers (now serious collector’s items) that graced collector’s vehicles until they disintegrated under our fierce Arizona sun.  So when our Legislature decided to recognize wulfenite as our State Mineral it seemed right to recognize that love, update the bumper sticker slogan with that missing “D”, and make it our Show Theme as quickly as possible.  As it turned out 2019 was as soon as we could do it. 


 Mineralogically, wulfenite is lead molybdate and forms in the oxidized, near-surface parts of lead-zinc-silver-gold deposits….of which we have many in Arizona!  When originally described from the Bleiberg (Lead-Mountain) District in Austria, it was called “plumbum spatosum flavo-rubrum”   but mercifully it was renamed “wulfenite” in 1845 in honor of Franz Xaver von Wulfen who had written extensively on the ores of Bleiberg (https://www.mindat.org/min-4322.html).  Wulfenite crystallizes in the tetragonal system (remember this year’s show theme?) as flat, square, tabular plates, often with pyramidal bevels along the edges.  Elongate, dipyramidal crystals are locally common and pseudo-octahedral examples are known.  Twinning is common but inconspicuous.  Although wulfenite has a high index of refraction and is often transparent and gemmy with bright yellow, orange and red colors, it is a poor gemstone because it is soft (2.5-3) and brittle.  Nonetheless, it makes very attractive faceted stones for the careful collector.  Careful is the watchword for wulfenite collectors as it often forms spectacularly beautiful…but equally fragile groups of crystals on crumbly matrix.  (Los Lamentos, the famous Mexican wulfenite locality is a notable exception to this.)

 Many wulfenite occurrences are characterized by enormous open cavities lined with yellow, orange or red crystals…often growing to several inches across. Until just after WWII, wulfenite was one of our major sources for molybdenum (which gives stainless steel strength at high-temperatures and corrosion resistance) so tragically, some large wulfenite occurrences were mined and processed simply for their molybdenum content. The famous Tiger Mine, just north of Tucson, produced 6.3 million (!) pounds of molybdenum oxide (MoO3) (www.janrasmussen.com/pdfs/Arizona%20Wulfenite.pdf).  That means at least 8,500 tons of wulfenite were mined, which jibes with stories of miners raking bright orange wulfenite crystals off the walls and shoveling them into wheelbarrows to haul to the smelter!  [For a really scary perspective, this would make a solid cubic wulfenite crystal about 35 feet on an edge]  Fortunately, after WWII, metallurgists and miners figured out that it was easier and cheaper to extract molybdenum from the sulfide mineral molybdenite…which occurs in HUGE deposits like the Porphyry Copper mines around Tucson…so our remaining wulfenite occurrences were left for collectors to enjoy.  Curiously, for some reason wulfenite does not typically form in molybdenite-rich systems, a fact which has been well documented by scientists at the Arizona Geological Survey…including our own Jan Rasumssen (then Wilt) (See Wilt, Keith and Theodore, 1984:  https://pubs.usgs.gov/of/1984/0830/report.pdf). 

For equally mysterious reasons, Arizona and neighboring parts of northern Mexico are exceptionally well endowed with wulfenite occurrences…including many of the world’s best known: Red Cloud, Glove, Los Lamentos, Rowley, San Francisco, Tiger, Ojuela, Defiance-Silver Bill, Santa Eulalia, Hilltop and Tucson’s own Old Yuma Mine.  A good guess is that a combination of long-lived arid conditions and slow, but deeply penetrating oxidation acting on rocks and mineralization of the right compositions led to this preponderance of wulfenite occurrences, a supposition that might be borne out by comparison with other places where wulfenite abounds like the deserts of southern Africa, Iran, Australia and China.


 Because wulfenite is such an attractive and popular collector species it is very well represented in the mineral collecting literature. Articles focusing on wulfenite in particular regions like Arizona are worth boning up on (cf, see Rasmussen reference above) and Lithography's books American Mineral Treasures and Collecting Arizona that went along with our 2008 and 2012 Shows feature superb in-depth articles on specific Arizona wulfenite localities.  Mineralogical Record has featured articles on specific localities practically since its inception (See especially the Arizona and Mexico Special Editions).  As always, Rocks and Minerals February issue spotlights our Show Theme, so next year’s issue will feature Arizonan and Mexican wulfenite locality articles written by familiar names…like TGMS VP Les Presmyk…and me! 

 Check out your local library for many colorful and informative resources on wulfenite before the Show so you can amaze your friends with how much you know about wulfenite.  If you’re lucky you might get hooked and join the legions of (sure-fingered…the stuff can be fragile) wulfenite collectors…there are almost as many of us as there are fluorite collectors!


Children's Museum

The Tucson Gem and Mineral Society is always willing to go out into the community and talk about "rocks!" We had two opportunities this summer to do just that ... here are some pictures when we were at the Tucson Children's Museum this summer. Everyone got to look through the microscope, view fluorescent minerals, see how minerals relate to their everyday lives and even take mineral specimens home with them. We had a GREAT time!

"Libraries Rock!"


TGMS has been involved with several community outreach programs.  We had the privilege recently to be involved with another one at the Murphy-Wilmot Library.

On Saturday, June 2, 2018, five TGMS members spent a couple of hours at the library for their "Libraries Rock!" day and boy did we have a good time! 

We set up five stations that parents and  children could visit and have a hands-on experience. 

The first station was "How Minerals Affect Your Life."  They were shown calcite, talc, quartz, copper (to name a few) and how they are used in products in our daily lives.  Plus, they got to see what the actual minerals looked like and hold them in their hands.

Then we had the micro mineral station.  Everyone had the opportunity to view four micromounts (dioptase, vanadanite, gold and kammererite) through the scope ... lots of kids enjoyed that!  They loved the colors and couldn't get over how small the minerals were with the naked eye but how big they were through the scope.

Next we had the UV fluorescent display ... our display had the blacklight always on so you can see the fluorescent minerals.  Tim McClain added a standard LED light that showed them how the minerals would look normally when it was turned on.  That got a really big WOW!

The last two areas were crystal models and "collect your own rocks."  We had seven crystals models that could be cut out and put together and then they could collect their own rocks through five boxes filled with goodies.  The fun part was the box with the "sharks teeth."  Everyone really enjoyed them and the number one question was, "Are these real?"

We had a great day.  The library really appreciated what we did (said they want us back again).  Within a two-hour period we had over 60 people (parents and kids) visit our displays.  Makes you feel good when parents and kids thanked us for being there .... makes all our effort worthwhile. 

So to , Victoria Fila, Marilyn Reynolds, Diane Braswell, Tim & Pat McClain ... "Thank You!"

"Kumihimo anyone?"

One of the fun things about being a member of the Tucson Gem and Mineral Society is the ability to participate in our educational classes. 


On May 17, 2018 we had our very first "Kumihimo Braiding Class!"  Sharlene Baker and Barb Elliott very graciously consented to teach a "beginner's" two-day class.

With the first class, everyone learned the process of Japanese braiding.  They learned how to calculate the length of material that would be used for the finished length of their necklaces, how to tie the beginning knot, set up the pattern, attach the weights and, last but not least, how to take it off the disk, tie it off and attach the jewelry ends.

They were able to purchase the Kumihimo basic kits.  It came with the material to begin their first necklace, instruction sheets, weights, Kumhimo disk, jewelry end caps and, above all, the guidance of two really great and patient instructors.

Both classes were to be only two hours long but, because it was so much fun, each class lasted much longer than that.  Everyone made Sharlene and Barb promise that more classes would be taught and on different techniques on braiding and weaving.

Moral to this story, become a member of the Tucson Gem and Mineral Society and join in on the fun!!





The 100 - A Practical Guide to Mineral Collecting in Today's World

"The 100 - A Practical Guide to Mineral Collecting in Today's World"

By Bill Shelton

A Special Publication of the New York Mineralogical Club, Inc.

“Based on Bill’s many years of mineralogical experience, “The 100” was a list that included the most important, and likely the most common minerals, in all of our mineral collections.”          

 “…..it has been one of the most popular series of articles published during the period I have been the NYMC’s Bulletin Editor.”                   

 “…….we decided to “preserve and protect” this series of articles in this Special Publication of the New York Mineralogical Club.”
“……the alphabetical listing appearing later in the book makes it easy to quickly find information about a given mineral……”


Mitchell Portnoy
Editor, Bulletin of the New York Mineralogical Club

TGMS has 100 copies of this special publication for sale. For its content and information, it is very modestly priced; it is being sold for $15.00.  Proceeds from the sales will benefit the TGMS Library Fund.  You can contact the TGMS Office at 520-322-5773 or tgms@tgms.org for more information.

How Good Is Your Imagination? Part 2


This is your final look how crystals are put together before the 2018 Show – Crystals & Crystal Forms. So, what have we learned thus far? We know there are six basic crystal systems – isometric, hexagonal, tetragonal, orthorhombic, monoclinic and triclinic. And we know that these designations are based on how the atoms in minerals fit together. The elemental atoms are arranged in a series of seed crystals whose interiors have imaginary lines, or axes, of different lengths. And that these axes meet at various angles in the center of the mineral’s seed. Like atoms attach to this seed and result in the macro crystals we see with our eyes. We’ve addressed the first three – isometric, hexagonal, tetragonal. Now let’s look at the remaining three – orthorhombic, monoclinic, triclinic.


Orthorhombic diagram

Orthorhombic diagram

Let’s go to your imagination and visualize the orthorhombic crystal system. There are three axes that intersect at right angles, 90 degrees, in the center of the seed. The isometric and hexagonal systems we looked at earlier have a similar axis arrangement with axes of equal length. The difference here is that each axis is a different length. What might a mineral in the orthorhombic crystal system look like? You may see combinations of distorted octahedrons, pyramids and prisms. Some minerals that crystallize in this system include barite, sulfur and topaz. There are two models for you to cut out and assemble – an (click on) orthorhombic block and a (click on) basal orthorhomb.

Monoclinic diagram

Monoclinic diagram

The monoclinic crystal is next to consider. We still have three axes of different lengths compared to one another. Two of them cross at right, 90 degree, angles, while the third is perpendicular and at a 120 degree angle. Crystal shapes may resemble prismatic blocks like orthoclase feldspar or swords like gypsum. Other minerals that crystalize in the orthorhombic system include azurite, epidote and papagoite. To add to your crystal model collection we’ve provided a (click on) basal monoclinic model and an (click on)  octapyramid.

Triclinic diagram

Triclinic diagram

Lastly, there’s the triclinic crystal system. This one will really give your imagination a workout. There are only three axes, but they are all different lengths in relation to one another and they intersect at different and odd angles. There are only two subdivisions in this system, unlike the others with multiple subdivisions and classes. Basic shapes are prisms and pyramids but they are highly distorted. We’ve given you two models to assemble – an (click on) octahedron and a (click on) basal pyramid. Albite and microcline feldspars crystallize in the triclinic crystal system, as well as chalcanthite, manganbabbingtonite and turquoise.

How Good Is Your Imagination?

How Good Is Your Imagination? - Part 1

By Anna Domitrovic  

 We’ll be taking a look at the six crystal systems in this article (Part 1) and the next article (Part 2). But, unless you’re a crystallographer, you’ll need a good imagination to make sense of how crystals are put together and the way they look to the observer. The focus for this installment will be the isometric or cubic, the hexagonal and the tetragonal crystal systems. There is an order to the way the atoms of an element or compound congregate to form a geometric shape. Since that arrangement starts at the atomic level, you’ll need to close your eyes and visualize that arrangement. But keep in mind as well, that the crystal forms we’ll talk about are not as perfect as the models we’ve given you. Mother Nature has a habit of putting her own spin on crystallography.

Pic 1.jpg

Let’s start with a relatively simple and common crystal in the isometric crystal system. Crystal forms are cubes (pyrite, halite), octahedrons (fluorite) and dodecahedrons (garnet), but there are many, many forms and subclasses. Ever hear of a dyakisdodecahedron. Well, it exists in the isometric crystal system. Let’s go back to the ones mentioned previously. Picture a perfect cube. There are three imaginary lines called axes that intersect in the middle of the cube. Each axis is of equal length and at a 90 degree angle to one another. That is true for every form in the isometric crystal system. Some other minerals that are in this system include copper, gold and silver. How many more can you think of? The models I’ve included to represent this crystal system are (click on) the cube and (click on) the octahedron.

pic 2.jpg

The hexagonal crystal system is the next one to take a look at. A form you may be familiar with includes prisms or barrel-shaped crystals (beryl, mimetite, vanadinite). Scalenes and rhombs (dogtooth calcite, rhodochrosite) are also forms common to this crystal system. Some crystallographers would like to take minerals like calcite and rhodochrosite out of the hexagonal system and put it in another similar one called trigonal, but for our purposes, we’ll call them all hexagonal. Imagine four axes for this crystal system. Three of them are equal in length at 120 degree angles from one another. There’s a fourth one, perpendicular to the other three and different in length. Some other minerals that crystallize in this system include bobdownsite, corundum, fluorapatite and pyromorphite. Once again, how many more can you add to the list? You have a model for (click on) the hexagonal dipyramid and (click on) the rhombohedron.

Picture 3.jpg

Now let’s look at the tetragonal crystal system. We’re back to three axes. Two of them are equal in length and at right angles to one another. The third is perpendicular to the other two, but can be either shorter or longer. Crystals may look similar to those in the isometric system, but they are either stretched or compressed along that third axis. Arizona’s state mineral, wulfenite, fits into this crystal system. Others include chalcopyrite, matlockite and scheelite. And the crystal models you have to work with are (click on) the tetragonal dipyramid and (click on) the tetragonal prism.

Well, I’ve really given your imagination a workout. I hope that the diagrams and images help you to understand what crystallographers are up against. As I said before, many of these crystal forms are not the ideal geometric shape. But practicing with actual mineral crystals is a good exercise in taking your imagination to reality. Give it a try! And stay tuned for Part 2.


TGMS Family Fun Day!!

TGMS Family Fun Day - Saturday, September 30, 2017

By Pat McClain

At a TGMS Board meeting recently, the subject came up about community outreach programs.  After tossing around several ideas, I came up with the suggestion of having a "Family Fun Day!"  This would give us the opportunity to showcase to the Tucson community what the Tucson Gem and Mineral Society is all about, utilize all the wonderful talent that we have in our membership and maybe, just maybe we could actually get families to come to our facility and learn something about the earth sciences, all while having fun.  I said to the Board that we could pull this off but only with their help ... well they really did!

After we had some TGMS members on board for the project, we had two or three meetings where we pulled all of our ideas together and we came up with a game plan.  We decided to have a cave crawl, rock identification, mineral identification, microminerals and micromounts, mineral uses, rock dig, metal detecting, meteorites & meteor-wrongs, fossils & evolution, fluorescent minerals, gold panning and a rock crusher.

IMG_3099 (2).jpg

Everyone who volunteered to work on this project really came through in flying colors; they worked really hard on the areas that they had signed up to man.  Ron Gibbs really deserves a special "thank you" because he is the one that brought our idea of "spin the wheel and win a prize" to fruition.  He found a bike wheel, made the stand, painted all of the red and green dots and made sure that it was in balance so that everyone would have a fair chance to win a prize.

A BIG "thank you" to Linda Oliver for donating time, talent and material in helping us to put together our fluorescent tent. We had one little boy that was so fascinated with the fluorescent minerals, his mom had a very hard time getting him to go look at anything else.  And "thank you" to Kent of Kent's Tools for donating all of the gold pans that we gave away.  It made a lot of kids happy!  A special "thank you" to Gene & Jackie Schlepp, who donated a wonderful group of mineral specimens.  When it came to spinning the wheel and if it landed on a "gold TGMS logo," the kids got to choose from these very special prizes. You should have seen their faces when that happened!

We advertised in as many FREE online event calendars that we could, in hopes that we were getting the word out to everyone.  Sometime before the doors opened on that Saturday, there were a few volunteers who were wondering if they were just going to be staring at each other for most of the day.  We all let out a hoot when the first parent and child walked through the door right at 10:00 a.m. and the most wonderful thing happened ... they kept coming ... all day long!  In a five-hour period we had close to 200 people walk through our doors.  And the best part was that most of them were children! 

Our volunteers were - Marilyn Reynolds and Victoria Fila manning the door, giving out mineral passport cards and raffle tickets. Mary Kirpes not only made the paper mache cave (with other volunteers), she was directing traffic all day; Ortrud Schuh manning the rock identification; Bill Shelton and Jennifer Isbell doing the mineral identification; Ron Gibbs, Brad Gibbs, Mark Ascher and Tim McClain focused on micro minerals; Mark Marikos explained the mineral uses; Diane Braswell kept the kids busy by helping them dig in the sand for all sorts of fun things; Roy Parson was in the dark all day long, he did the fluorescent mineral display, and helping him was Beverly Lynch who made sure that all the kids had their cards stamped (she was also very adept at directing the folks to our outside stations). Mark Candee handled the meteorite right and meteor-wrong table; Christina Marikos, Kalen Krause and Wyatt Ingalls did a great job with the fossils; Louis Pill and Bob Melzer had fun showing kids what you could do with a metal detector; Kerry Towe was out in the sun all day (even with the tent) explaining the fine art of gold panning; Myles Ingalls got to make some noise with his rock crusher; Jerry and Mary Glazman where in charge of "Spin The Wheel and Win A Prize"; Bob and Jeannette Barnes handled the sale of the snacks; Mike Hollonbeck and Harry Lutzow were our "grand gophers" for the day; Rose Marques and I did our best to make sure that the "details" were taken care of before, during and after.  

I think it is safe to say ... "It was a success" ... and I am pretty sure that we will do it again.  It truly was a "fun day!"

Comments we received on Facebook:

Lauren Rae Layton Ard - We had a LOT of fun at this event!  Heard about it from Arizona Families and we are so glad we came!  My Kids are really, REALLY excited about their new rock collections and are even decorating special boxes to keep the rocks in, etc.

Larissa Kaliszewski - We had a great time, you guys put together an enjoyable event!  Thank you!