Thursday, December 5, 2019

Cotton Candy Agate for the Holidays?

BECOME A ROCK SHOW VENDOR?  See my article in the December issue of Rock & Gem Magazine! 

When I first saw a slab of peach and white cabbing material, I thought it looked like a sweet confection; then I saw its name, "Cotton Candy". It fit.

Then I showed it to an older rockhound, who authoritatively told me it was "Youngite". Being a curious sort, I decided to find out if they were one and the same thing. Frankly, I thought it was likely they were, but appearances can be deceiving.

YOUNGITE

Youngite (SiO2 ) For many years, this was a popular slabbing material that was not terribly hard to find even though it was only mined in one place inside the Youngite caves near the Glendo and Guernsey reservoirs in Guernsey, Wyoming. The  online expert on this stone is Mike Nelson, I got my information from him personally and his blog site, check it out: Click Here

Mike says  Youngite is a brecciated reddish-brown to peach jasper that was then re-healed by deposition of cream-colored chalcedony.  Often the entire rock is then covered by druzy quartz crystals.  At one time Youngite was fairly common on the market as collectors were able to pull numerous specimens “off the walls” in Youngite cave(s) and voids near Guernsey.  He says he understands that the caves are in the Guernsey Limestone and the breccia clasts are actually derived from the limestone.  


Image Credit: Midat.org





This image shows the common exterior with botryoidal  drusy quartz coating. The quartz portion is fluorescent, which is the quickest way to discover whether you have true Youngite. The Cotton Candy stone is not fluorescent, even though it often looks the same.



Credit: Mike Nelson






Unfortunately, the area where the Youngite was mined is  reported to be mined out and the specific area is no longer open to the public. There are some pieces available, generally at a pretty high price point. If you're considering investing in some, I suggest you ask the seller for regular and short-wave pictures from the same angle to be sure you're getting the real deal.

COTTON CANDY

When I described my Cotton Candy slab and told him I believed it came from Mexico, that explained a lot of the differences between the two similar rocks.  Most of the agate in that part of Mexico comes from volcanic rocks like Retaliate nodules rather than sedimentary limestone like Youngite. The brecciated materials in both probably get their color from iron in them.

So, they really are very different rocks. 


IN MY SHOP



I purchased this slab as "Cotton Candy" at a local rock show.  As you can see, it's pretty dirty and my impression was that it was quite weathered, which turned out to be true. The colors changed dramatically when I worked with it.
My finished cab from the slab above,

You can see the pencil marks I made around the void that has the druzy coated botryoidal shapes and that I used to set the shape.

After I got it cut, shaped, and polished, you can see the yellow-looking matrix has become white with a touch of blue tinge.  The peachy material has finished out as pink and there are obvious bands around the void and the pink. It took a lot of scrubbing to clean the interior shapes, but it was worth it.




My Youngite cab






I had purchased a small slab of Youngite years ago without knowing what it was, and made a cabochon with it. How do I know it's Youngite and not Cotton Candy?  It's fluorescent! 

Youngite contains chalcedony and quartz, so it fluoresces mostly green. I tried my teardrop cab above under the long and short wave lights, but nada. That was a real surprise since the botryoidal formations inside the vug appear to be quartz druzy, but they obviously aren't.

To see how Youngite lights up, check out the image on Mindat.org at Click Here.


Also, when you look at the two cabs, you'll notice how very similar they are. But, a very close examination of their mineral components shows that they are not the same thing at all. Sort of like green gemmy faceted stones. Are they apatite Ca5(PO4)3(Cl/F/OH) or are they emeralds
Be3Al2(Si6O18)? The only way to know for sure is to consult a gemologist.

From a lapidary standpoint, I feel that both materials are excellent lapidary material. They are nice to work with and take a beautiful polish. I would caution about what I noted earlier. Because of its current rarity, real Youngite commands a relatively high price in the market.  Cotton Candy is commonly available. If you are considering a purchase, be careful you get what you pay for.

Until next time, I hope  you find joy (and great rocks) through the holidays you celebrate this time of year.

Your Lapidary Whisperer,

Donna







Saturday, October 5, 2019

CRAZY FOR CRAZY LACE AGATE

I loved working with the peach and white stone


Crazy Lace agate is a lapidary dream rock. It's basically a banded calcite, but it's so much more! The bands can come in almost any color, they can swirl, encase spheres, bend in fortifications, and even feature druzy coated vugs.  This stone is mined in the Mexican state of Chihuahua. Some claims in the area name the area name of stone after itself like the Noriega. And yet . . . Rodeo Flats agate from Arizona looks pretty much the same as does some agate mined in Morocco. 



This slab isn't high quality, but I love the pattern








Did I say any color earlier? Well, when it comes in all blue, sold as blue crazy lace, it's definitely not from Mexico. Blue lace agate primarily comes from Namibia and South Africa with a bit in Romania. You'll often see them sold side by side with other lacy-patterned agates, but they are far distant cousins.
 


   
This Crazy Lace has color and motion


In case you're wondering, I included this picture because I could!  This one is so chatty that it won't slow down and tell me what it wants to have done with it. So, for now it's safe . . .

although . . .

if you look at it from either side, you can see landscape scenes with a bit of blue sky.












The slab has the beautiful sunsets I hope to use 


THE LAPIDARY EXPERIENCE

 As the Lapidary Whisperer, I adore this stone!  The colors and patterns tell me so many stories, and the stories can change simply by moving the templates around. It is also fun to create shapes by using a pencil to create the shape that shares the story the slab is trying to tell you. I've found that on occasion, I can incorporate the outer edge as a feature in the cab.

This slab is driving me a bit crazy. It wants me to use the sunset orbs, but the problem is they are very shallow and don't even show on the back of the slab, I'm afraid if I do any grinding, they'll disappear completely.

The good news/bad news is that this is not a fast mineral to work. It runs right about 7 on the Mohs scale and tends to take a while to work, especially on the lower number grit wheels. The good news is that it will take a nearly gem-like finish.

Be aware that if the colors of your crazy lace are unusually intense, it may be dyed and the colors will fade over time, especially if exposed to the sun.  If the intense coloring is limited, like the slab below, it is probably natural. 

A busy natural slab with red staining

HISTORY?


I found only a few references to the history of this stone and the conflicted like . . . crazy! One source claimed it was first discovered in the late 19th century, and then forgotten until a construction crew found it when they were clearing land for road construction in the mid twentieth century.

Cerridwen, image: Bing

Yet, it had apparently already been discovered in Mexico long before the Spanish Conquests by pre-hispanic people who used it to appease the gods or as an amulet for those fighting wars. I even saw a site that credited this stone to Cerridwen in Celtic mythology (Gods of Ireland, Scotland, Wales and Gaul)  heaven knows how they got rocks from Mexico.



While I'm not into assigning mystical property to minerals, I saw several places where it was referred to as the "happy stone". Okay, I'll partially buy into that. Working with crazy lace in my shop does make me happy, because it makes such incredible cabochons.





NOTE: Except for the image from Bing, all the other images are mine. If you want to use them, please ask.

Until next time, I'm your LAPIDARY WHISPERER

Donna

Thursday, September 5, 2019

SAGENITE - THE ROCK THAT'S GOING PLACES

A rock that insists on telling you a story is a great rock to get to know! This Sagenite Rutile is an amazing storyteller. I see a wheel in motion over a coarse surface. What do you see?
Credit: Marco Campos-Venuti Collection






According to this site Sagenite can come in geometric patterns  This variety is formed when a pattern of crossed Rutile crystals is present with angles of 60 degrees that is the twinning law of Rutile. 
Credit: Marco Campos-Venuti Collection
Sagenite loves to tell stories. At least the kind I work with in my lapidary shop does. There are apparently two schools of thought when this name is used to describe a rock. There's the one that describes stones with vibrant, puffy strands that appear to be moving with an unseen tide. I absolutely love these. The other is a variety of rutile  where the crystals criss-cross  in a geometric sort of pattern. The look is so distinctive that back in 1796, it was named sagenite  from the Greek and Latin word "sagena" or net. This piece looks positively architectural to me.



MY SAGENITE

I haven't been able to acquire any saginite rutile to work on, but I've had a lot of fun with the kind that makes soft swirls.

 I fell in love with the slab I used to create this cabochon!  It has the yellowish Sagenite, along with white tube structures you can just see inside the clear agate, and a vug that comes across as a whirlpool that is causing the Sagenite to swirl around.
Pat McMahan, renowned agate expert, wrote that these Sagenetic filaments are often arranged in fans or sunbursts in the agates and can come in different colors. That is because the Sagenite in Agates is a pseudomorph (where one mineral replaces a different one that has already created the shape). As an interesting aside, he feels that the Sagenetic structures form in the still-hardening agate and they don't extend into nearby banded agate which is formed at a different time.

.
This cool piece of Sagentic agate really shows off the way the filaments can arrange themselves in groups of fans.

The way it has a central open space in the agate with the filaments swishing around it, makes me think of that sight you see when you're in your car as it goes through the automatic car wash. All those soft things rotating and slapping your car as you go through.


The vendor who sold me this had a lot of slabs of this material. I asked him what it was and he wrote "Sagenite" on the slab I purchased.

I've had other people who have seen it agree that it is Sagenite, but it's different from my other pieces because there's no cluster that the formations spring from.

However, I love the look like it's from a pot of spaghetti and it polishes like a dream!





 Do you have a favorite agate cabochon that features sagenite?  I'd love to see a picture of it!

ROCK SHOW SEASON IS JUST AROUND THE CORNER. I'd love to hear from you about what makes your show (or your favorite show) special. Don't forget pix!  Send to Donna@LapidaryWhisperer.com


Until next time, have fun with your rocks!

Your Lapidary Whisperer

Donna

Monday, August 5, 2019

PETRIFIED IN A BLUE FOREST





 The first time I saw this incredibly blue chunk of what looks like part of a limb, I had to have it. I'd never seen anything like it before. Petrified wood with blue bark! It looks to me as if the blue chalcedony formula changed a bit over time as the material directly in contact with the wood is darker than the material on the top. It appears that it once was botryoidal but the cool bumps were worn down.

It turns out there is only one area known to have this particular material; the Blue Forest at the west end of Eden Valley, Wyoming.  Don't let the the name of the place fool you, it may have been a forest in the Eocene Era, but now it's pretty desolate now.





NOT JUST BARK

Credit: Mindat.org




This image of Blue Forest petrified wood where the chalcedony filled the center, shows both gradation of color due to minute changes in the mineral content of the water when it was formed as well as a botryoidal lining in the center.

Side comment, I love to say the word botryoidal. It's somewhat lyrical. Don't know how to pronounce it, check out Daniel's example at Here






ORIGINS

In the Blue Forest of Wyoming, about fifty million years ago, it is believed that a volcano erupted in the region, knocking the trees over. The area where they fell is swampy and algae quickly enveloped the wood, preserving the shape. Over countless years, the wood cells themselves decayed and the space was taken by agate, quartz and silica primarily, along with a variety of minerals. There can be a range of blue colors created by the inclusion of tiny amounts of manganese, iron, copper and titanium.



Credit: Jim Snowden







 
This cool image of botryoidal blue is courtesy of Jim Snowden at Blue Forest Petrified Wood Their site is one of the places I visited when I researched this blog post. I encourage you to visit them for information or to purchase amazing specimens.





  NOT ALL BLUE WOOD IS FROM THE BLUE FOREST

Some of my Arizona wood showing blue.




While this area is unique in its presentation of petrified wood with blue chalcedony bark and inclusions, blue chalcedony is not, itself, rare.  Blue can also be found in other petrified woods, especially from Arizona, where the wood is often multi-colored. 




In the image at the top, the wood did not shrink as it was being petrified and you can see that the wood grain was very well preserved. In some cases, the wood has shrunk creating voids that are filled with the blue chalcedony, which leads to . . .

Blue Forest with gold chalcedony 
At the San Francisco Mineral & Gem Society show this weekend, I saw (okay, I bought) this chunk of rock from the Blue Forest. I took the picture dry, but wet, even the wood has a blue hue. In this case, the bark is rough golden chalcedony. In this situation, when the wood petrified, it shrank, allowing flows of blue and gold chalcedony and a bit of white quartz. It reminds me of some boulder opal I got some time ago, except that while the blue is lovely, it's no opal!

LAPIDARY STANDPOINT

I've made a number of cabochons from petrified wood. They chatted with me and helped me create some amazing cabs.  If you're hoping to see an image of a Blue Forest cab here, it may be a while. So far I can't bring myself to slab my new acquisition even though it is thick enough, and I'm afraid if I try to slab the quarter-round specimen at the top, the blue will detach.  Darn.

Have you ever worked with this material? I'd love to see your photos!

Until next time,
Your Lapidary Whisperer,
Donna





Friday, July 5, 2019

MARIPOSITE - LAPIDARY WORTHY?

My Mariposite yard rock.

The green and white that make up Mariposite make it an attractive yard rock. But as they say in the television commercials, there's MORE!

WHAT'S IN A NAME?

When miners during the California Gold Rush discovered they could find gold and placer gold in the green and white rocks around them instead of standing in a cold creek with a pan, they named the rocks Mariposite for the town they were standing in. (Not a huge imagination happening here, but a great way to tell others where to find it).


It can be found in many areas around the world, where it is mostly called Mariposite, except for Canada where they call it Virginite for some reason. Now, if you want to check my research, please check for Virginite on Google. When I checked on Bing, their articles under "virginite" were not about rocks. Nuf said.

WHAT IS MARIPOSITE?

It's actually not a mineral. Depending on how you want to think about it, it's either a metamorphic rock or a conglomerate. Chromium-rich Mica give the rock its green color and its flash. Dolomite Marble or Quartz provide the matrix. 

Mariposite slab



CAN I CAB IT?

 That depends on your willingness to handle disappointment. First, let's examine the hardness on the Mohs scale of the mineral which compromise the rock

Mica       2.5-3 
Dolomitic Marble  3.5-4
Quartz  7

As you can see, the Mica and Marble are similar in hardness, but soft as heck. If you want to cab it, plan on making it into a pendant where the edges are encased or it won't last long.  When the Mica is next to Quartz, undercutting is a real problem. 

I decided to create some Mariposite flowers for this blog post. Not my best idea ever. You can see that  I got one (of several tried) flowers. The plan was to make three and make a divot in the center that would hold a crushed yellow rock/epoxy mix to make it look like a flower. 

Flower start in Mariposite 


The first one came out fine. A bit rustic, but that was what I was looking for.  The others, even though I was using 220 grit and higher, shattered. Apparently, this rock is known for, basically, falling apart. I plan to try to get some more done so I can make a flower arrangement, but I think I'll need to drop them on the floor first to see where the slab breaks naturally.

OTHER USES

Aside from gold mining and cabs, Mariposite has traditionally been used for other practical purposes including being a facing stone for buildings or fireplaces and even markers in cemeteries (although I suspect they weathered so quickly that their messages were soon lost).

Have you worked with Mariposite?  What was your reaction?

Until next time, your Lapidary Whisperer,

Donna