Wednesday, April 11, 2018

BIG CATS AND OTHER ZOO-THEMED JASPERS


Leopard Jasper Slab:ption


Some time ago, I wrote a post about zoo-themed jaspers. Since then, I've been able to acquire two big-cat themed slabs I really love.  So I decided to update this classic blog post with the new materials. Another reason I went back and updated this post was that I realized I had a number of cabbing materials that weren't just named for animals--they were petrified remains of animals! I'm working on a future blog post about those materials . . . and I bet you'll be as surprised as I was about how plentiful and varied they are!

BIG CATS

The Leopard Jasper at the top of the blog has a lot of amazing stories it wants to tell this Lapidary Whisperer.  I see a red brick wall separating the wilderness above and the homes, fields, and streams below.

The Cheetah Jasper, on the other hand, tells stories of camouflage in the wild and stories hidden behind the dots.
Cheetah Jasper

ZEBRA JASPER

When I first posted this blog, , I was looking through some slabs, and the Simon and Garfunkel lyrics, "It's all happening at the zoo," came to mind. On the table, I had slabs of zebra jasper and some beautiful tiger eye.

So I wondered, are there many other stones that could be zoo animals?  Yup! Here's the line-up of the ones I found in my shop.


The zebra is something I found at an estate sale in San Francisco. The shop equipment and contents were being sold after an old rockhound went to that amazing lapidary shop in the sky.  I was pretty new at the hobby then, and I was entranced by the stark black vs. white coloring and the fluid lines of the rock. I took a few pounds then, now I wish I'd bought all there was.


TIGER EYE

Tiger Eye
This cab is from a smallish strip I purchased at a rock show. The first thing that struck my eye about it was how the brown intrusion on the large end drains like a lake through the most chatoyant part of the stone down to a blue tiger eye space. To me, it's a story stone, because of the way the color and the movement work together. For example, if it's not a lake draining to the bottom, what if it were a blue volcano with the brown smoke going through a bright sunset?  I believe this tiger eye originated in Western Australia where it is called Marra Mamba.

One thing I love about working tiger eye, is that with a Mohs scale hardness of 5.5-6, it is soft enough to work fairly quickly, but still hard enough to take a wonderful shine!




Snakeskin Jasper
SNAKESKIN JASPER

Okay, let's start with the fact that I have no idea why it's called snakeskin when it's red. I'm not sure I've ever seen a red snake.

The parallel red lines do remind me of a snake and I can almost see it slithering along, but really . . . Maybe it's a special zoo snake.



KAMBABA "Crocodile" JASPER

Kambaya "Crocodile" Jasper






As jasper goes, crocodile is reminiscent of the animal, but it's a long way from being the most attractive stone out there. It does give the overall impression of a crocodile skin, I haven't been able to get the cabs from the piece of rough I purchased to take much of a shine. I've been using cerium oxide on canvas. Has anyone out there had a better result with another polishing medium?


 




SHOULD BE AT THE ZOO

When you look at a piece of petoskey stone, don't you think of a tortoise shell? It really has that vibe, but I didn't see it called that anywhere. You can see images of petoskey stones at http://www.tribal-software.com 

So, these are the zoo animals from my workshop rocks. Do you have any "zoo" named minerals you're working on or any minerals you think should have zoo names?  Send me a note with a picture, I'd love to see it!

Until next time,

Your Lapidary Whisperer,
Donna

Wednesday, March 28, 2018

FASCINATING FLUORITE





My favorite thing about Fluorite is the way it mimics other stones. For example, if I had cut a long, thin strip of the slab above and then cabbed it, it could appear to be Tourmaline. It can even look at bit like Amethyst if you get the pictures just right.

Fluorite 

 KNOWING IS HALF THE BATTLE

There's a HUGE difference between Fluorite and Amethyst or Tourmaline as any lapidarian can easily tell.  Fluorite is only a 4 on the Mohs harness scale. Amethyst is a much harder 7 and Tourmaline is a 7-7.5. So working it for lapidary purposes has two problems. First, it doesn't take much of a polish (full disclosure: the Fluorite pictures for this blog post were taken when the rocks were wet). Second, because it is so soft, unless you coat it with a shellac or something similar, it will scratch easily.

A cool piece of somewhat fractured green fluorite

NOT NAMED FOR ITS LOOKS!

This mineral was officially named by Carlo Antonio Galeani in 1797. His inspiration was the fact that it was used as a flux in iron smelting to reduce the viscosity of slags. He gave it the name from Latin "fluere", to flow. Over time, fluorite has also been used as a flux in the manufacture of some glasses and enamels.

BUT LOOK AT IT NOW!

According to Nightsea.com  Sir George Stokes (1819-1903), a mathematics professor at the University of Cambridge, gave the effect its name. In the early 1850’s Stokes noted the color shifting effects in the mineral fluorspar and investigated in greater detail. A key experiment was using a prism to isolate ultraviolet light and observe blue emission. He was first inclined to call this ‘dispersive reflection’, implying a reflection to a different wavelength. He wrote:“I confess that I do not like this term. I am almost inclined to coin a word, and call the appearance fluorescence, from fluor-spar, as the analogous term opalescence is derived from the name of a mineral.” I agree with Stokes, dispersive reflection doesn't sound half as nice as fluorescence.

Natural light

Same cab, back-lit with UV light



I'm finding his whole fluorescent thing pretty interesting and I'm planning to do a blog post on it soon!

GIVE ME THAT FLUORITE GRIN!

Yes, the fact that the mineral "Fluorite" and the toothpaste additive "Fluoride" sound alike is no accident; but don't try rubbing your mineral samples on your teeth.

The Food & Drug Administration has approved three compounds, stannous fluoride, sodium fluoride and sodium monofluorophosphate as toothpaste additives to prevent cavities. The compounds are manufactured by reacting sulfuric acid with fluorspar, a calcium fluoride ore.

It apparently doesn't take much. The box for my Crest Complete lists sodium flouride (NaF) as the only active ingredient and it is only 0.243% of the product.

Hope you enjoyed this blog post. If you'd like to comment, go through the instructions at the bottom or email me directly at Donna-at-LapidaryWhisperer.com

Until next time, I'm your

Lapidary Whisperer

Donna Albrecht






Wednesday, March 14, 2018

"BIRDSEYE" VIEW

 
When I found this nifty rock at the Arizona show in February, I immediately realized it was something I've seen before, and it was called Birdseye  Rhyolite because of the distinctive orbs it contains. Then I went to look it up on mindat.org and discovered they don't recognize Birdseye Rhyolite. The only "Birdseye" designations they recognize are for a a shale and a quartz that I'd have called "Crazylace" (See Mindat.org image).

Photo Credit: Mindat.org

FUN FACTOID
According to Wikipedia, the name rhyolite was introduced into geology in 1860 by the German traveler and geologist Ferdinand von Richthofen . He named it using the Greek word rhýax ("a stream of lava") and the rock name suffix "-lite".    

This Baron von Richthofen is better remembered in different circles as the grandfather of Baron Von Richthofen, the WWI aviator famous for is daring flying skills and remembered fondly by fans of the rock and roll band The Royal Guardsmen who loved this song. Listen here.

METAMORPHIC, IGNEOUS, OR SEDIMENTARY?

Because of it's rough, coarse texture, I thought it  might be sedimentary. (Dear readers, I've never studied geology and have an enthusiastic amateur's growing base of knowledge in the area--still needs to grow a whole lot). Okay, again, I thought it looked like sedimentary, but then I started doing some research.  

Rhyolite is actually an igneous rock, like Obsidian!  Huge surprise there!  It turns out that if  the lava cools too quickly to grow crystals, it is Obsidian, a natural glass. When the lava cools more slowly it forms crystals that result in rhyolite, pumice, or tuffa. It can also result in textures including layering, spheres and nodules.



As sometimes happens, but is never welcome, this stuff seemed to almost melt in the saw. Before I was done with a few slabs, the oil was the dark orange color and had thickened up quite a bit.

This is the first slab I decided to cab. As you can see, it has some nice light pink orbs towards the right edge along with an iffy dark section above them. 

I roughed out an oval. This is the "B" side.  Notice the grey streaks through the material. More about them later.















Then I turned it over to the side I'd originally planned to use and the pink 'eyes' are even more dramatic when they're a bigger part of the picture. I was concerned about the grey material at the top seemed a bit friable. However, it didn't go all the way through the depth of the slab so I decided  to deal with the uneven gray material by cabbing that as the top surface. Those big "eyes" had it!



WORKING THE STONE

As I mentioned earlier, this stuff made a thick mess of my oil and did the same to the water when I was grinding it.  The gray stuff ground to a nice polishable surface and I wondered what it was. When I discussed this with another member of one of my rock clubs, he suggested it might be Hematite or Magnitite.  So I got out my handy tester--a paperclip hanging from a thin sewing thread--and proceeded to hold it over the rock. Bingo!  The paperclip started dancing and my dark lines and upper edge were definitely Magnetite.

Now, Rhyolite is a  6-7  on the Mohs Scale and Magnetite is more than 5.5, so they seem pretty well matched in terms of grinding and polishing. In this particular rock, the Magnetite was actually a bit harder, making it more difficult to keep from getting sinking areas between the lines.  Difficult, but not impossible.

TA-DA!



 I'm pretty happy with the final cabochon. It's not as shiny as I like, but then the material wasn't all that hard. If you look carefully at the center blossom, you can see a bit of magnetite at the 11 and 3-5 hour marks around it as well as some faint lines.

Next time I play with it, I'm thinking about using some Opticon on a slab and seeing if that makes it enough harder to take a better shine. Think it will work?









Hope you enjoyed my blog! Until next time, I'm your Lapidary Whisperer,

Donna

Wednesday, February 28, 2018

TEMPTED BY TOURMALINE!





Watermelon Tourmaline


 I fell in love with tourmaline the first time I saw it. I saw gemmy tourmaline at shows and sales and marveled at the colors and the way it handled light. I bought the Watermelon Tourmaline above from another collector. The face is only three-quarters of an inch across, but if you're looking at it on a computer screen and it looks huge, well, that's the way I see it.

I love watching the light shine through the deep rose red and green. I'll never cab this piece, in part, because I'd hate to lose it as a specimen, and in part because when I look at it closely, I see lines that make me think it's been fractured before and might not hold together on a grinder.

 But before I got my hands on that gemmy specimen, I had purchased a bargain selection of crystals at a rock show. As you can tell from the picture of the size of the crystals I bought, money was no object when making this purchase. 😁



PRETTY IN PINK


 This pink specimen is in my case. It's not very gemmy, but when I hold it I can clearly see the crystal structure in the white matrix and that's why I had to bring it home with me.

 Then . . .






PURPLE PASSION

Then I went to Quartzsite and Tucson this year. It was unbelievable!!! I saw some tourmalines
in matrix that wasn't gemmy at all, but had personalities that tickled my cabbing bone. This rock and the next are fairly friable, which added challenges to the cabbing process.

In this specimen, you can clearly see the dark rose tourmaline--and see that it isn't sparkling. The matrix in this case is white and clear quartz, but again, not a terribly high-quality quartz. I cut some slabs and worked on a cabochon to see what would happen,







I was delighted that this material cabbed without any stabilizing support. However, since it was somewhat smooshed (a technical term (?) for crushed over and over until it was a conglomerate), there were no clearly defined edges.

The finished cab took a nice polish and I love the way it looks. It's sweet and romantic and reminds me of violets.









BITS, PIECES, AND TOURMALINE

I purchased this conglomerate rock, because it had black tourmaline, quartz, and mica on a rhodo matrix. This picture shows the colors as pretty muddy. It also tells the story of the fractured character of the specimen. A quick run through a saw, told me how friable it was.

I took it as a personal challenge!




 DA-DIDDA-DA!!! I took some slices and treated them with Opticon. Then they held up to my Genie and I was able to work them into cabochons.

The pink rhodo looks a whole lot better after it's been polished than it did in the original rock. In this image you can also see the clear quartz and smooshed black tourmalite.








 WE HAVE A WINNER!

 In my last post, I offered this slab of millefioria-style glass to the person who sent me the best name for it. The responses were wonderful!  Two of my favorites were "Montana Wildfires" and "Swept Up to Heaven".

The winner was the  one who made me laugh. Vic McPherson named it "Oozite" because of the way the columns seem to be trying to ooze out of the slab. Vic, it's on its way to you!
 

I hope you enjoyed my post. I love reading your comments!

Until next time, I'm your Lapidary Whisperer,

Donna Albrecht

Wednesday, February 14, 2018

MY ADVENTURES WITH MILLEFIORI GLASS--MAYBE

* WIN A FREE SLAB *


I've always admired the Millefiori Glass when I've seen it in beads and pendants. The bright colors and patterns that remind me of the late 1960's (Flower Power anyone?) and were pretty tempting. I also love kaleidoscopes, and the Millefiori glass I'd seen looked somewhat like it was at the end of my kaleidoscope.  I'd tried a few times to get my hands on some, but until my trip to Arizona this month, I hadn't had any luck.

Then I saw it in a tub in Quartzsite!

Bricks of the stuff! The reds, the blues, and the green were spectacular. The tiny flowers would bring a smile to Grinch's face. So I bought some and brought it home.

I love this stuff so much I have to share it. If you want a FREE SLAB, see below!

 



.



GLASS BRICKS--THE ANSWER TO THE PROBLEM OF GETTING DIFFERENT ANGLES.

This red brick is about six inches square and about 1.5 inches thick (see the end cut above). There is some sort of silvery material around the brick, probably glass dust. Notice how the parallel lines on the side gave me a lot of new possibilities!




The reason I wanted bricks instead of slabs was because I was fascinated with the possibilities of cutting and cabbing it that weren't just a strait cut parallel to the blossoms. I wanted to do cabs, and I wanted to cab the glass on angles showing off the material inside.

This is a piece I cabbed from the green block I purchased. The colors are bright and it almost looks like there's some weird choir singing through the glass.



BUYER BEWARE

In my haste to acquire these beautiful bricks at such a good price, I didn't ask too many questions. I'm sure none of you have ever done that . . . The good price? Well, the show was a few days from closing, so I figured I got lucky. Maybe.

After I got home, I gave myself some time to take a better look at the bricks. They were still beautiful, but, darn if there weren't some flaws. But even world famous Millefiori Glass from Murano would occasionally have a bum batch they'd sell off cheap, right?

No.

Because of the history and craftsmanship of the Millefiori Glass made in Murano, Italy. It is the gold standard. Other places may make a similar looking product and even use the same techniques, but they aren't the same. Many are undoubtedly lovely, but it's similar is using the word "Champagne" to describe a bubbly wine. While there are many wineries that produce extraordinary bubbly all around the world, only wines made from grapes grown in the Champagne area of France and grown and produced following specific guidelines are actually Champagne. 

WHAT MAKES MILLEFIORI GLASS, MILLEFIORI GLASS?


According to Wikipedia, "Millefiori is a glasswork technique which produces distinctive decorative patterns on glassware. The term millefiori is a combination of the Italian words "mille" (thousand) and "fiori" (flowers). Apsley Pellatt in his book Curiosities of Glass Making was the first to use the term "millefiori", which appeared in the Oxford English Dictionary in 1849. The beads were before then called mosaic beads."

Okay, that's a start.

My next step was to send some pictures of what I had purchased to Client Services at Glass Of Venice, a distributor of Millefiori Glass art. Julia wrote back quickly, "In our opinion this is not authentic Murano Glass. Similar slabs made in China can be purchased on Alibaba for a low price of $16 per kilogram, see this listing as an example: https://m.alibaba.com/product/60475870290/Wholesale-colored-millefiori-glass-brick-for.html 
Millafiori Pendant GlassofVenice Click

Murano masters typically do not sell Millefiori Glass in bricks, Italian Millefiori Glass is available either in rods or in the finished form. Murano Millefiori is entirely handmade using the ancient method, which is very labor intensive and results in high prices."


I checked the website and you have to purchase a whole lot of the stuff to get that price. Also, checking around, I discovered that the Murano glass is generally sold in rods or bits of rods, to be assembled, fired, and finished by the glass artist.


HISTORIC ROOTS

On their web site, Glass of Venice, they share this history of the beautiful glass.
"In the sixteenth century some of the Murano (Italy) glass artisans started attempts to imitate the beautiful ancient glassware created by Romans. They were successful in doing that, but as with many other glassmaking techniques, the secret they uncovered had subsequently been lost again until the interest in these Roman pieces sparked anew in the second half of the nineteenth century.

Millefiori Pendant from GlassofVenice Click
At that time when archeological discoveries became more frequent and many beautiful decorative items were unearthed, Murano glass artists again became fascinated with glassware from classic antiquity created by the ancient Romans and exhibited in the famous Murano Glass Museum.

Some of the beautiful objects that came to us from those times include glass vases, bowls, urns, and plates with flower or abstract patterns spread around the inside and outside surfaces of the objects.

Venetian glass artisans understood conceptually that these items were created using glass rods shaped in various patterns and then cut up and fused together. For more information on the history and creation of Millefiori Glass, check out Click Here

WAS THIS A GOOD PURCHASE?  

You might think I'd be disappointed to know that the millefiori-style glass I purchased wasn't the real deal, but you'd be mistaken.

I LOVE this stuff!       


I think the parts with flaws, make the viewer wonder 'what happened there?' which is another way of creating a story. The parts that don't have flaws? That's a story of its own.  I'm going to keep working with it from time to time and see what other stories it has to share.




* WIN THIS SLAB*




As you know, this Lapidary Whisperer, has rocks that tell her their stories which I try to incorporate into whatever I make of them. So, I'll send this slab to the reader in the U.S. who gives me the name or story for this stone I like best. If you work it, I'd love to run a picture of what you made on a blog in the future. If you just like the slab, no problem. The story doesn't need to be more than a sentence or so, just let me know what you see in it.

The slab has angled sides. The even, flat part is roughly 1.25 x 1.25 x .25 inches.

Send your entry to me directly at Donna@LapidaryWhisperer.com 

Tell me a story!

Until next time,

Donna








Wednesday, January 31, 2018

Ebony & Ivory Cabbing Minerals


Ebony and Ivory, the juxtaposition of black and white always captures the imagination.


The white and black can describe polar opposites in good vs. bad, light vs. dark, the absence of color vs. it's darkest expression. We know that it has inspired music, like Paul McCartney and Stevie Wonder's  "Ebony and Ivory" that pleads for understanding across racial lines.

On the lighter side, it's the name of a variety of crape myrtle bush,and when I spent too much time Googling the phrase, I came up with a novel based on Celtic lore with that title.
 
LAPIDARY ON REAL EBONY AND IVORY

Ebony wood comes in varying shades, and the pure black is prized. It's exceedingly dense, so dense that it won't float in water!  From a lapidary standpoint, that denseness means it will take a superb polish.

Elephant ivory is extremely difficult to get legally, and probably best not pursued. On the other hand,you can legally get ivory from walrus tusks, or the two front teeth of elk that are believed to have been tusks in ancient history. If you want to do some ivory cabochons that will really gross people out, wart hog tucks are ivory too.

So for this blog post, I'll just use minerals that give that Ebony & Ivory feeling, without a spec of either one in their make-up.


OBSESSION WITH OBSIDIAN

For my money, snowflake obsidian makes a wonderful ebony and ivory match,although, black obsidian is actually very, very, very dark brown. Chip a tiny bit off and hold it up to a bright light, you'll see! There are also lighter brown obsidians, but that's for a future blog.

The "snowflakes" in the obsidian are actually cristobalite. As you know, obsidian is  igneous (volcanic stone) and has no crystals. It is primarily made of silicon dioxide  (Sio2) with other minerals, However but when some of it cooled , bits of pure silica formed crystals leaving these fascinating inclusions.



 

  A GARDEN IN STONE

Perhaps the closest to ebony and ivory is this free-form slab of dendritic opal. The white here is the creamy white of old ivory piano keys and the black dendrites remind me of the growth of trees--like ebony. And yes, if you're wondering, these stones have not only been talking to this Lapidary Whisperer , they won't shut up!






AN OLD FAVORITE SNEAKS IN

I couldn't resist putting a pinolith cab in this blog post. It's a real favorite to work with. The shapes tell all sorts of wonderful stories. If you want to know more about this fascinating stone, check out my blog post on it.




 WILD WILD-LIFE PATTERNS

This round black and white jasper is called zebra jasper, which gets us back a bit to the animal kingdom from a previous blog, but it's not animal, it's just a cool-patterned jasper. In my experience, it takes a really nice polish and gets a lot of "oohs and aaahs" when I show it off.



 

PETRIFIED WOOD

I wish I knew where the slab I made this cab of came from. It's defined by the squiggly lines that look almost like scrimshaw.  







 I hope you enjoyed this post as much as I did preparing it. Please feel free to respond in the comments section  below or write to me directly at Donna@LapidaryWhisperer.com

I'll be back in two weeks with some new musings by this Lapidary Whisperer.

Donna Albrecht


Wednesday, January 17, 2018

The Unnatural Life of Created Cabochon Material




When I think of rocks for my lapidary projects, I tend to think of minerals in their natural state. When I think of lab-created mineral products, I think of gemstones like sapphire or diamond. But there is actually a third category that falls roughly between the two. The truly unnatural cab materials.

The way I see it, Ray Bridewell's home-grown crystals are at the top of the heap. They are bright and gemmy and take an amazing polish





I made this incredible free-form cabochon using material I purchased from Ray. He makes it by melting quartz and other materials to 2300 degrees Fahrenheit and letting the cool slowly over a period of weeks. As it cools, crystals bloom inside the new slab.




 This pink cabochon is made of the same basic material and as you can see the spikes are thicker and there is almost microscopic sparkling dots adding a completely different look to the finished cab.

I'm going to give him a plug because I love this material so much and so will you.  Contact him at
Bridewell Stone Studios, https://www.facebook.com/BridewellArt/
 to see what he has available now.










SLAG GLASS

Slag glass is a fascinating mix of manufactured (the glass) and the artistic patterns that are formed when it is dumped into a heap. It's not so much  a cold-blooded product like goldstone (see below), but a happy combination of the way the different colors are disposed of into a glass slag heap.

For me, this comes right under Roy's crystals because while it is pretty and shiny, it lacks the gemmy look of the other.

Slag glass is excess material from the glass making process. It is often cast aside as undesirable--unless of course, you love committing lapidary on it.

I found this yummy piece as a random slab at a rock show. I loved the movement it contained and decided to take it home and let it tell its story. You can clearly see some aspects of the rock supporting the cabochon through the transparent sections. 






 ALL THE STARS IN THE SKY - GOLDSTONE

You know when something is too good to be true . . . but it isn't?

Goldstone is often found at rockshows and in jewelry. I've been told at various times that it was mined in Russia or South America and that the flecks were real gold.

Image Credit: Wikipedia
Great story; but not true. If a seller tells you this, assume anything else they tell you about their merchandise is equally untrue.

However, it can also be truthfully called adventurine glass, stellaria, or monkstone.

It comes in two steps below Ray's crystals because of its uniform consistency. Ever notice the difference between a natural granite slab countertop and a manufactured one?  The natural one will generally have inconsistencies that pull your eye around the surface. The uniformity of the manufactured ones is lovely to look at, but without the inherent charm of the natural.

Goldstone is a glass product made in a low-oxygen environment. According to Wikipedia, "The most common form of goldstone is reddish-brown, containing tiny crystals of metallic copper that require special conditions to form properly. The initial batch is melted together from silica, copper oxide, and other metal oxides to chemically reduce the copper ions to elemental copper. The vat is then sealed off from the air and maintained within a narrow temperature range, keeping the glass hot enough to remain liquid while allowing metallic crystals to precipitate from solution without melting or oxidizing.

"After a suitable crystallization period, the entire batch is cooled to a single solid mass, which is then broken out of the vat for selection and shaping. The final appearance of each batch is highly variable and heterogenous. The best material is near the center or "heart" of the mass, ideally with large, bright metal crystals suspended in a semitransparent glass matrix."


START YOUR ENGINES!

As you know, most Fordite is a single color with swirls showing the way the material settled and hardened. Sometimes it's called Motor Agate because it is made by layers and layers of automobile paint that was sprayed at cars and has hardened to a product that can be cut and polished into cabochons.

This comes in last of the four lapidary materials covered in this blog post. It just doesn't have the pizazz of the others and isn't as likely to talk to me about what it wants to be as the others.

When I was in Quaratzsite  last year, I saw one block of Fordite that really caught my eye.  It consisted of the primary colors of red, blue and yellow. It was so cheerful that I just couldn't resist.

It's fun to work with and makes beautiful slabs and cabs (doesn't this one look almost like a button for a child's outfit?). But if you get some, be careful not to work it with too rough a grit.  If I used anything rougher than a 220 grit on my wheel, the little bits of color had a tendency to fly off.

I'd love to hear about any unnatural materials you use for cabbing. Drop me a note!

Until next time,
Your Lapidary Whisperer

Donna

Wednesday, January 3, 2018

GEODE CHANNELS--ARE THE MINERALS GOING IN OR OUT?




Have you ever seen what looks like a passageway between the inside and outside of a geode and wondered what is was?


 I love the colors and swirls of this geode and the way it shows the passage. It reminds me of the art work by Judy Chicago called "The Dinner Party".
Photo Credit, Dave Kleesattle. 



From the few I've seen, I always assumed the material was flowing in through the passage and coating the inside of the empty geode.  Then I heard a different theory.

ONE FASCINATING OPINION


Dave Kleesattle
Dave Kleesattle, a geologist and rockhound, did a program at the Contra Costa Mineral & Gem Society on what he had learned years ago to call Einflusskanalen (which translates from German as "Influence Channels".

His theory was that the channels were formed when the crystals formed inside the geode, thereby creating pressure on its walls. Then at a weak point on the wall, the pressure created an exit, reducing the inner pressure to a manageable level.

I understood where he was coming from, but that didn't explain situations like the one in this image below where you can plainly see that at some time, horizontal layers formed inside the geode. I was perplexed.






MY THEORY

Photo courtesy of Dave Kleesattle. 


Now, I've always suspected that the passage was from a crack or weak point that allowed mineral-saturated fluids to enter and over time the liquid evaporated, leaving space for the next layer to enter. In my theory, years when the mineral-rich water filled the open geode, it coated the interior walls. When there were years with lower quantities of water entering the geode, you got the horizontal layers. Notice in this geode that there are layers covering the irregular edges as well as a section of white and red horizontal layers.





TIME TO CALL IN THE EXPERT!


Brad Cross

To find the definitive answer to what the passages sometimes seen in geodes do, I called on Brad L. Cross, co-author of Geodes Nature's Treasures (Gem Guides Books, 2006)

He wrote, "It appears you have run into the same perplexing question that all of us “students of agates” have encountered, “Are these mysterious features we see in agates (and some geodes) an entrance or exit channel?”  I’ve been a serious agate collector/student for 45 years now and Donna, I simply don’t have a solid answer to your question.  I might add that I am far more than an “armchair collector,” I’ve conducted a tremendous amount of field research on various agate deposits and I find nothing that provides a concrete answer. 

Photo credit: Dave Kleesattle
"For years I felt that these “conduit channels” were an entrance point for mineralized fluids.  However, I can show you specimens where that channel never reaches the outer edge of the agate, highly suggesting it was an exit channel generated during crystallization of the agate.

My personal opinion is that we are likely seeing both entrance and exit channels.  One of the things that us agate students must always remember when we are looking at these features is that we are only seeing a surface or two-dimensional view.  The question arises,“What is the geometry of that tube deeper into the agate?”  While the view we have in hand shows the tube not reaching the outer rim or edge of the agate, it may very well reach the surface several millimeters deeper in the agate and we are simply not seeing it in the view we have in hand.                       

"I can assure you of one thing – the question of whether these are entrance or exit channels will continue until the end of time.  We do not have a solid answer today and unfortunately we’re not going to have an answer when you and I leave this ole earth.  Very little solid science or research has been conducted on agates – primarily because they have no economic value to industry.  No one wants to sink money into expensive research when there is no monetary return for their investment dollar.  That’s primarily why we have no solid answers today on these unusual features. 

Photo credit: Dave Kleesattle
"For now, simply enjoy these features in agates as a mystery we may never hold the answer to.  Perhaps it’s that unknown that makes agates and geodes so interesting and attractive.  IF we knew the answers to all of the questions these incredible specimens possess, they simply may not be as interesting and attractive to us."   







I'd like to thank Brad and Dave for the help they gave me with this blog post. Obviously, this is a fascinating topic, and barring amazing money for research on this topic, Brad's explanation is the best we'll ever have.

 SHAMELESS PLUG

I purchased Brad's "Geodes: Nature's Treasures" at a rock show. While it doesn't discuss the channels I've been exploring in this edition of my blog, it is a comprehensive guide to all things relating to geodes. The pictures of remarkable geodes like I've never seen before are well worth the price of the book alone.

If you're interested, contact GEM GUIDES BOOKS  at www.gemguidesbooks.com or order them on Amazon.com


Until next time, when I'm writing about The Unnatural Life of Created Cabochon Material,

Your Lapidary Whisperer,

Donna