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Post by sheltie on Aug 27, 2013 16:36:09 GMT -5
So there I was, hiking at 11,500' in the mountains around Austin, TX , when I looked down and saw a bunch of pretty agates. They turned out to be Morrocan agates, very unusual for this area. So I picked up about 25 lbs and brought them home. This is an example of what the slab looks like. It's kinda funny in that before I slabbed it, the color was a very light blue. Not so much tight now. (Ok, maybe it was a flight of fantasy about the mountains, but the box of agates is truthful. Ok, maybe I bought them and didn't find them but then the story wouldn't be so good).
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Post by kk on Aug 27, 2013 17:05:15 GMT -5
Nice banding, should make for some interesting cabs.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Aug 27, 2013 17:21:03 GMT -5
That is a great slab. The problem I have with slabs like that is trying to figure out how to get more than one cab out of them. I have some carnelian that is the same. I will be waiting for the cabs from that. Maybe I will learn something. OR you may have the same problem as me and we are stuck. lol Jim
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Post by sheltie on Aug 27, 2013 18:08:02 GMT -5
Jim, My efforts end with the slabbing. Anything beyond that is determined and done by the boss of the family. I'm on a 12 step plan for my addition but it isn't working.
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Post by deb193redux on Aug 27, 2013 20:00:14 GMT -5
go a little further and cook them. thegemshop uses Moroccan agates to make tuxedo agate and then they charge $150/lb for slabs.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Aug 27, 2013 22:17:23 GMT -5
Very nice agate. That's the banded material they treat to make Tuxedo Agate.....Mel
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Post by rockpickerforever on Aug 27, 2013 22:30:24 GMT -5
I always thought Morrocan agates were found in Moroocco? (Yes, I read your story, wise guy!)
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Post by helens on Aug 27, 2013 22:46:20 GMT -5
Those are really pretty!! I thought Morrocans were red tho?
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Post by sheltie on Aug 28, 2013 8:15:28 GMT -5
go a little further and cook them. thegemshop uses Moroccan agates to make tuxedo agate and then they charge $150/lb for slabs. I've never heard of this, could you explain it and the process a little more?
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Post by sheltie on Aug 28, 2013 8:17:42 GMT -5
Those are really pretty!! I thought Morrocans were red tho? All the ones I've seen in the past have been blue although I know there are red ones. I'll look at the ones I got but I think they are all blue (I bought a medium size box full of them).
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Post by deb193redux on Aug 28, 2013 15:20:11 GMT -5
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Post by deb193redux on Aug 28, 2013 15:23:15 GMT -5
Those are really pretty!! I thought Morrocans were red tho? some berber agates are red. a lot are just gray & white banded. it is a whole country with a number of different types of agate. you would not say "I thought American agates were mossy"
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Post by helens on Aug 28, 2013 15:26:30 GMT -5
So do they turn red when cooked, or black like tuxedos?
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Post by sheltie on Aug 28, 2013 15:54:16 GMT -5
Thanks for the links. The pictures are striking. For a number of reasons I won't work with acid. I guess I jumped to the conclusion that in addition to using acid, you could literally stick it in the stove at x degrees for x minutes. I guess that's not the case.
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Post by helens on Aug 28, 2013 15:58:34 GMT -5
I know Daniel's tried amazing experiments in turning them black with acids... I was just wondering if they turned red with heat (and no acid)? Or would heat change them black?
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Post by deb193redux on Aug 28, 2013 19:34:30 GMT -5
there is no iron to turn red with heat
but you can use sugar and heat about 450 to turn dark brown/coffee
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Post by helens on Aug 28, 2013 19:47:20 GMT -5
Ahh... so all the red Moroccans are different from the rest because they have iron... okies. Thanks Daniel:).
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Post by deb193redux on Aug 28, 2013 21:17:40 GMT -5
I don't know red moroccans real well. I am not sure they are red from iron, but that is most often the reason for red agate. but there are other reasons. I don't think red moss is due to iron.
but when heat treating turns a rock more red, redish brown, or orange red, it is because of accelerated oxidation of iron impurities. I do not know if you can unambiguously conclude iron from red in the absence of heat treatment.
"The colors seen in nature, in this case agates, are commonly caused by what are called chromophores, certain elements which have some electrons which easily change their energy levels. Iron, copper, nickel and chromium are examples. When trace amounts of these are present, the colors that we see can occur."
The question is what other red chromophores are out there.
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Post by helens on Aug 28, 2013 21:45:36 GMT -5
Well, the corals that turned red in heating all started out yellowish, so when the stone is starting out greyish, it may not have enough whatever chemical to go red. I wasn't thinking about that... but makes sense:).
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,558
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Post by jamesp on Aug 28, 2013 22:07:55 GMT -5
White,grey and black rarely change. Makes sense. Very likely there is little iron. Typically yellow turns orange. Orange turns red or brownish red. Red often turns brown or darker red.
But other colors from who knows what happens in the coral. Often the color-coral. Go figure. And lavender or purple.
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