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Post by Toad on Apr 23, 2006 9:25:22 GMT -5
I spoke to an old guy who's been doing the lapidary thing for 30 + years. I told him I had agate and jasper tumbling together. He said that the jasper would wear away to nothing before the agate was finished.
Is that true? My gem book has them both pegged at 6.5 to 7 hardness, so I would think it is fine to mix.
That said - my leopardskin jasper seems to be doing okay while the banded red/yellow jasper is disappearing. Did I just get bad banded jasper or is the guy right?
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rockhard
starting to spend too much on rocks
Member since March 2006
Posts: 227
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Post by rockhard on Apr 23, 2006 9:56:54 GMT -5
I have some banded red & yellow jasper that's softer too. I believe that some have more clay or colored organic stuff in them, making them softer. The ones that are more completely silicified, generally shinier (in breaks) when rough, are harder. Doesn't mean it's bad unless the stuff won't polish and falls apart.
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Apr 23, 2006 10:07:09 GMT -5
Agate tends to the harder end of things (the 7 to 7.5) while Jasper to the softer (6.5) now a banded or brecciated jasper my be falling apart because the "cement" holding it all together is too soft- Not really the fault of the jasper- just one of those natural quirks- that happens- as for tumbling them all together- well I do it all the time- and have very few problems-
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Apr 23, 2006 10:13:05 GMT -5
True jasper and agate should be about the same hardness and tumble well together. The problem is there are lots of common names for marketed materials that are incorrect thus causing confusion when choosing what to tumble together. Many rhyolites are called jasper. Leopardskin Jasper is a rhyolite for example and often has softer areas as are many of the so called picture jaspers. Guadalupe Picture Jasper Clam Chowder Jasper, Indian Script Jasper and Silver Lace Onyx are in the dolomite-travertine group and way softer than agate or jasper (3-4 in hardness) and so on. You can scratch test for the travertine types as a nail will scratch them and not agate or jasper, but the nail will not scratch rhyolite. It usually just winds up being a matter for experimentation and experience.....mel
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Post by gemkoi on Apr 23, 2006 13:11:44 GMT -5
YA Mels right on. I would say, i see more ryolite or mixtures being called jasper, than actaul jasper these days. its become such a common practice, that it effects the novice the most. Which is a bummer becasue that can discourage folks just getting started. I always tell folks true jasper wont be sandy or gritty on a fresh break. If it is, its not really jasper.
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Post by Bikerrandy on Apr 23, 2006 18:20:24 GMT -5
I've tumbled all sorts of jasper with agate, some does great and some will grind away. Picture jasper always seems to hold up nicely with agate.
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Post by rockds on Apr 24, 2006 8:26:39 GMT -5
I think mel said it best, true jasper and agate do fine together - I do them all the time
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jrtrio
has rocks in the head
With10 tumblers tumbling the sound is so delicious!Send me more of those little red fellas, please?
Member since February 2006
Posts: 535
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Post by jrtrio on Apr 24, 2006 20:16:51 GMT -5
Also, Mel was correct about the Picture Jaspers having the softer layers in them and he used the term "so called" picture jasper. That's what I would call any "picture" jasper that has sporatic places of the lined "pictures". You can see this in the Georgia Queen Picture Jasper. But, if you are tumbling these kinds of Jaspers and want to get a better shine out of them you can bake them. Doing so will usually darken the colors of the bands but it hardens every layer so much so that the more compact layers come out feeling like agate before you polish and they take on a shine much faster and look "glassier" after polishing. Here's a link for heat treating your rocks and pet woods etc. But, I wouldn't want to deal with a spouse by tying up the oven for close to 24 hours! So, I stayed at 200º for an hour then a half hour at each 50º addition, then when I reached my target temp I kept it there and went to bed. BUT I'm not a normal sleeper!!! I don't sleep anywhere near 8 hours so, don't try this at home unless you have a great alarm, won't mind sleeping on the sofa for a few nights, and you'll have to open your widows to vent the odor of baking rocks!! But, it is something that I will do again seeing as I'm one of the luckier people here and have a wife that puts up with a LOT of my crap!
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Post by Toad on Apr 24, 2006 20:17:18 GMT -5
Thanks for all the info, you all.
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