pamee83
starting to shine!
Member since December 2008
Posts: 38
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Post by pamee83 on Jun 7, 2009 14:20:14 GMT -5
I want to tumble some onyx and have been doing some reading and am becoming a little confused (not hard some days lol)
Onyx has a hardness of 7 yet I've read that it is hard to tumble as it is so soft.
I have a vibratory tumbler (5lb)
any tips or suggestions would be greatly appreciated
thanks
Pam
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Post by Michael John on Jun 7, 2009 14:30:18 GMT -5
The term "onyx" is often misused. Can you show a picture of your material?
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bushmanbilly
Cave Dweller 
Member since October 2008
Posts: 4,719 
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Post by bushmanbilly on Jun 7, 2009 20:59:20 GMT -5
The Onyx you have if I recall right is Candy Onyx. Has a hardness of about 5.
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MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
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Post by MikeS on Jun 8, 2009 8:41:49 GMT -5
I tumble mine just like any agate or jasper....if your material has a hardness of 5, I'd throw some plastic spacers in with it to cushion it a bit...
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pamee83
starting to shine!
Member since December 2008
Posts: 38
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Post by pamee83 on Jun 8, 2009 22:38:36 GMT -5
Bushman, I am not talking about the candy onyx, thanks tho
i don't have the rock yet MJ, but i don't want to waste my time either buying or hunting for something that won't tumble/polish well. I have a project that requires rock of 7 mohs, i was reading that onyx is 7...
guess i will just rethink the idea of using "onyx"
Thanks mikes....i have some of those and will use them if i end up tumbling anything that soft.
Pam
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Post by johnjsgems on Jun 8, 2009 23:11:53 GMT -5
The confusion is onyx is chalcedony with repeating patterns, hardness same as any agate or jasper. A lot of travertine is called onyx but isn't and usually has quotation marks indicating looks like onyx or "onyx like". Tumble it alone and it should be ok.
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Post by 150FromFundy on Jun 9, 2009 8:37:21 GMT -5
Scratch test your material for hardness. True Onyx is a 5. It is a matrial that is often carved into paperweights, ash trays, candy dishes and coasters by exploited child labour in third world countries. Onxy can be scratched (carved) by steel hand tools.
Chalcedony is microcrytsalline Quartz, so it is a 7. Chalcedony/Quartz will scratch most steel hand tools, but not tempered, carbide, or tungsten tipped tools.
Many rocks, especially those sold by merchants. rather than collected by geologists, are simply mislabelled. Don't trust the label. Trust the scratch test.
150FromFundy
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Post by Hard Rock Cafe on Jun 9, 2009 11:20:29 GMT -5
It looks like we still don't have agreement! LOL
fwiw: wikipedia agrees with John
Chuck
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pamee83
starting to shine!
Member since December 2008
Posts: 38
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Post by pamee83 on Jun 10, 2009 0:36:47 GMT -5
no easy answer to this one huh? lol
i'll try to stay away from purchasing onyx....thanks for the help everyone!
Pam
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