chromenut
fully equipped rock polisher
Member since December 2009
Posts: 1,971
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Post by chromenut on Dec 28, 2009 23:54:32 GMT -5
I searched the forums for Onyx and couldn't find anything so thought I'd post this here. Hope you don't mind. I'm wondering if anyone has any experience with tumbling either type? I have come across a supply of both, the Icey White is about a half pound slab that I want to cut down, most for tumbling but some for cabs. And I have black onyx all over my house from years of collecting it. Now time to do something with it.
Any suggestions, ideas, advice? Remmber, I'm a virgin so treat me gently!
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Post by Toad on Dec 29, 2009 8:09:40 GMT -5
Onyx comes in a lot of beautiful varieties and is often cabbed. Tumbling just needs to be done with care due to its soft nature. I'd probably tumble it by itself (no agates allowed). Expect to lose more volume than you would with a harder stone, but I think it would finish pretty well. Someone on here has tried it at one time or another. I'll let them chime in before I stick my foot in my mouth...
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Post by johnjsgems on Dec 29, 2009 9:43:47 GMT -5
Problem with "onyx" is most of it isn't onyx. Onyx is chalcedony in repeating patterns but hard enough to tumble, cab, etc. A lot of travertine looks like onyx, is called "onyx", but is limestone in alternating layers. Our local stuff cabs and polishes nicely but disappears quickly in the tumbler. I'd tumble it alone and check every day or two.
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Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Dec 29, 2009 9:56:34 GMT -5
Yeah, what John said. True onyx is hard, mohs about 7 while travertine onyx, being primarily a calcite type material with onyx type banding, runs mohs 3-4 or so, very soft for tumbling....Mel
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Post by deb193redux on Dec 29, 2009 10:51:03 GMT -5
I would get a quartz crystal point (Mohs 7) and a steel nail (~Mohs 5) and do hardness tests. FIgure out if you have true onyx (sometimes called sardonyx) or softer material often marketed as some type of onyx.
Some types like silver-lace or honey are in the middle. They are not as soft as the travertine onyx, but are only a little above Mohs 6. They generally cab better than they tumble, but solid bits without vugs and pits or obvious crumbles may tumble OK.
Anyway, let us know how hard your stuff is.
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Post by johnjsgems on Dec 29, 2009 10:58:58 GMT -5
"anyway, let us know how hard your stuff is" sounds like a lot of my spam mail messages.
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chromenut
fully equipped rock polisher
Member since December 2009
Posts: 1,971
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Post by chromenut on Dec 29, 2009 11:45:46 GMT -5
lol... so do the scratch test first sounds like good advice. I've not really done any rock grading yet, because everything I had was very specific and easy to tell what it was and known Mohs scale. Sounds like fun. As it stands now, I have enough small batches to do them with a single type of stone alone, and until I'm better at this than a beginner I'll be collecting stones until I have a portion of a single stone type to tumble together. Otherwise, it's to the cab they go...lol...
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Post by deb193redux on Dec 29, 2009 16:58:56 GMT -5
"anyway, let us know how hard your stuff is" sounds like a lot of my spam mail messages. I follow John. Imaging my frustration when doing a goggle image search for "beaver tail" <grin> |
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