earthdog
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Don't eat yellow snow
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Post by earthdog on Aug 13, 2007 21:54:55 GMT -5
I have to admit, I stopped at the Gem Shop a couple weeks ago when we were riding past Cedarburg. I asked if they had some more tuxedo agate, which they didn't, then Karen tried telling me that the woman that sits behind the counter making cabs all the time is the one that "invented" tuxedo agate and that it is a top secret formula that nobody knows. I bought five slabs of T.A. a couple years ago and I love the junk. I did a search on Goggle tonight and I am finding tuxedo agate from Morocco , India among other places. Gene told me a couple years ago that tuxedo agate is kinda "man made" It's a banded agate that is soaked in a honey solution for a long period of time then the honey is burned off with some type of acid that changes the color of the agate to the black color. It seems to me that they, at the Gem Shop make alot of claims to stuff that I find kind of far fetched. Does anyone know the story behind tuxedo agate?
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Post by parfive on Aug 13, 2007 22:02:46 GMT -5
I know it's dyed, it looks cool, and I doubt that soaking an agate in honey will accomplish anything.
Rich
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rollingstone
starting to spend too much on rocks
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Post by rollingstone on Aug 13, 2007 22:14:53 GMT -5
Gene must be very old, because the process has been around for 2,000 years, and was formally described (ie detailed instructions provided) in the early 1800's. ;D Here's a link, if you scroll down to the bolded section "carbon coloring", you can read exactly how to do it. -Don www.modernjeweler.com/web/online/Colored-Gemstone-Gem-Profiles/Black-Onyx/1$303....odd, I'm having a difficult time putting in the proper link... I think you can use the link above, and click on "black onyx" on the left-hand side to get to the same place. If not, what it says is, "Carbon Coloring Starting in 1813 and continuing through the mid-century, German cutters discovered a series of coloring techniques that allowed them to turn agates various colors: first red (carnelian) using heat alone, then, in 1819, black using what is called the sugar-acid process. Kurt Nassau summarizes the latter process in his indispensable book, “Gemstone Enhancement”: “Two liquids are…used for black agate, the first consisting of 375 grams sugar in 1 liter of warm water, having the consistency of thinned honey. After being soaked in this for 2-3 weeks, the agates are transferred without drying into concentrated sulfuric acid (very dangerous). After being heated for 1 hour and boiled for 15 minutes to 2 hours and then cooled, the agates are removed, washed well, and then dried very well at medium temperatures. The concentrated sulfuric acid extracts water out of the sugar, leaving behind pure black carbon.” More recently, a quicker, supposedly less permanent dyeing technique involving immersion and heating of stones in a cobalt solution has been used. But purists stick with the sugar-acid method first described by Pliny nearly 2,000 years ago." -Don
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Post by parfive on Aug 13, 2007 22:33:50 GMT -5
Well, I guess Pliny the Elder told me! ;D
(I ain't dunkin' none of my aggies in honey.)
Rich
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Sabre52
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Post by Sabre52 on Aug 13, 2007 22:34:37 GMT -5
Yup. I've heard it on good authority that Tuxedo Agate is dyed Moroccan Banded Agate. According an old volume of Gems and Gem Material I have, the agate must be soaked in honey or sugar solution for three weeks or more (375 grams sugar per liter of water). It is then placed without rinsing in concentrated sulfuric acid which is slowly heated for an hour and then boiled for 15 to 20 minutes. The container is the allowed to cool slowly when the agate may be removed and washed. It is then heated gently in an open crucible for several days to remove all traces of the acid. Apparently, considerable differences in final color tones may occur depending upon the permeability and saturation of the different silica layers. Basically though, this is how all the strong black and white patterns are achieved. All the other color treatments require other methods. All in all, pretty darn complicated.....Mel *LOL* Oops, Don and I must have the same books! He just types faster *L*.
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Post by Lady B on Aug 13, 2007 23:41:00 GMT -5
Neat thread. I love reading about the history of stones/stone names/stone designs. Thanks to all for the input.
Lady B
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181lizard
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Post by 181lizard on Aug 14, 2007 0:03:44 GMT -5
E... got a pic anywhere?
For cryin out loud...it better be awesome stuff after all the bother! LOL
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Sabre52
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Post by Sabre52 on Aug 14, 2007 0:18:54 GMT -5
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earthdog
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Post by earthdog on Aug 14, 2007 7:57:32 GMT -5
Sabre, Rollingstone thats how Gene explained it to me a couple years ago, exactly! It doesn't seem that tough of a process. I wonder if I could do it? There is a chemical place next door to where I work. Here are the slabs I got a couple years ago from the G.S. The largest is the size of a silver dollar and I paid $50 for all 5, crazy huh? This is what I ended up with,
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Post by akansan on Aug 14, 2007 9:17:40 GMT -5
Hmmm - a little more black and white than a botswana...
Does it make both colors more definite (the clear white and the *other color* black) or does the process really just work on one of the colors?
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rallyrocks
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Post by rallyrocks on Aug 14, 2007 9:29:01 GMT -5
The sugar/sulfuric acid treatment only imparts or darkens the blacks.
The same treatment is done to Andamooka matrix opal to darken the matrix and better show the fire.
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181lizard
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Post by 181lizard on Aug 14, 2007 11:22:02 GMT -5
It IS rather pretty!
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Post by ladyt on Aug 14, 2007 13:31:54 GMT -5
sulfuric acid (very dangerous). Extremely dangerous if you heat it. Don't breathe the fumes!!! Tonja
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earthdog
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Don't eat yellow snow
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Post by earthdog on Aug 14, 2007 21:35:55 GMT -5
I'd heat them outside.
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wades
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Post by wades on Aug 15, 2007 0:20:59 GMT -5
Gene must be very old, because the process has been around for 2,000 years, big snip “Two liquids are…used for black agate, the first consisting of 375 grams sugar in 1 liter of warm water, having the consistency of thinned honey. After being soaked in this for 2-3 weeks, the agates are transferred without drying into concentrated sulfuric acid (very dangerous). After being heated for 1 hour and boiled for 15 minutes to 2 hours and then cooled, the agates are removed, washed well, and then dried very well at medium temperatures. The concentrated sulfuric acid extracts water out of the sugar, leaving behind pure black carbon.” More recently, a quicker, supposedly less permanent dyeing technique involving immersion and heating of stones in a cobalt solution has been used. But purists stick with the sugar-acid method first described by Pliny nearly 2,000 years ago." -Don I have my doubts about this story. Unfortunately the English translation of Pliny at perseus.tufts.edu seems to be down so I can't check it, but I can't believe that he had any recipes involving concentrated sulfuric acid. (not that he would have called it that). The reaction described (using concentrated sulfuric to dehydrate sugars to elementary carbon) is plausible, but the stuff was unknown before the 8th century. European alchemists from the 13th century onward knew it as oil of vitriol, but they could prepare it only in limited amounts by troublesome and dangerous methods. I can picture some alchemist discovering the honey-soaked agate + vitriol -> black stone reaction: you might plausibly try that if you were attempting to transmute something semi-precious into gold. The value of the black stones would have probably been small compared to the cost of the vitriol though, at least until the 18th century when it became an industrial product (and not incidentally made possible the development of modern chemistry). Boiling anything in concentrated sulfuric acid definitely falls into the "don't try this at home" category. Most chemists would probably prefer to avoid doing it in a well-equipped lab.
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rollingstone
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Post by rollingstone on Aug 15, 2007 2:06:31 GMT -5
You may well be right that the process was not around 2,000 years ago. Even if it were, it must have been based on much more rudimentary technology than what the Germans outlined in 1819. But maybe there could have been something developed 2,000 years ago?... using acid from acid mine drainage or when rainwater mixed with the sulfur residue from early smelting efforts? Just speculating, the 2,000 year old process might be complete bunk.
However, even if it wasn't done until the German reference of 1819, that is 198 years ago, so the person at the Gemshop who claimed to Earthdog that someone there invented the process, would still have to be pretty old. ;D (In re-reading E-dogs post, I see that it was not Gene who claimed to have invented it, so I shouldn't have taken a shot at him, it should have been directed at whoever claimed it was invented by someone at the Gemshop.)
I wonder if they actually use the process at the Gemshop, or buy pre-made tuxedo agate from elsewhere? -Don
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Post by akansan on Aug 15, 2007 10:14:07 GMT -5
Hmmm... All in all, I'd probably be just as happy, oz. for oz., with another stone. It seems much more trouble than it's worth!
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WyckedWyre
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Post by WyckedWyre on Aug 15, 2007 11:11:08 GMT -5
Maybe it's me, but I have a problem with dyed rock of any kind. I appreciate the skill of a lapidary in bringing out the beauty of a stone, but I prefer my stone as Nature intended it. That's probably why I'm not particularly fond of "Rainbow Calsilica" either. It just doesn't look natural...
However, I do like Goldstone. Go figure. :-/S
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Post by flintfish on Aug 15, 2007 11:34:05 GMT -5
I love the science of the process - and wonder about loads of stuff - who first discovered this - and what were they trying to do?! but deep doen I agree with NMrocks, it's weird, I wasn't sure if goldstone was fake or not - in the UK we get mostly dyed agates in the crystal and rock shops. The main source was originally from Germany where dying agates became an art form - I believe they used Brazilian rough by choice, having worked out many of the productive mines in Germany. It's interesting, but not really real somehow. A bit like synthetic gemstones, ruby sapphire etc.. Saying that, if I had some I'd certainly polish it!
Cheers,
Harry.
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181lizard
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Post by 181lizard on Aug 15, 2007 13:34:19 GMT -5
I like the Tuxedo because while it's enhanced...it's still in the realm of "this is possible in nature." But I really do agree with Susan about the dyed vs. undyed. If it's hot pink or blue...I'm not really interested in it. Now...the goldstone is in a class all by itself. The history & lore of how it came to be puts it in the "I gotta get me some of that".
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