Mike I am new at rock tumbling also. I have Petoskey stones also. I read that since they are a soft stone you have to be real careful. The book told how to polish by hand. I tumbled mine for about 24 hrs. I used a medium grit. By looking at them, I am afraid to put them back in the tumbler with the polish compound. My plan is just spray them with lacquer. I haven't done it yet. Hope this helps. I am sure someone who has more knowledge and maybe has tumbled Petoskey stones would have more info then me.
I also have what you call 'soft Petoskey stones'. I know those cannot go in the tumbler or be hand polished. The book tells me just to put them in a pretty jar with some mineral oil. I was thinking about trying to spray just one of them with the lacquer and see what happens.
Mike, petrosky stone, as far as I know is a calcite. The coral it originates from has not gone mineral transfer. Of the few petrosky stones I have tumbled, I have so degraded the stone with all the polishes I was left with very little. A stone polisher I know, saves the final polish for the petosky stones after he cabs the original shape. He routinely mass final polished all his cabs I have never been able to final polish my cabs so I use a leather buff and cerium or tin oxide. I suggest if you have some choice samples, put them aside. Larimar is also similar. Do not tumble Larimar. If the only way I could polish petrosky stone was to tumble, I would do 220 for a few days, checking constantly. I would move up to 660 for a week, and run at least two weeks with cerium oxide. There might be some non mineralized organics trapped in the centers of the coral cells. Watch for gas build up. I once tumbled some fossilized buffalo scat and the tumbler had a soupy green mixture. There was no odor, but I suspect the mineralization was incomplete deep into the stones. It leached out with the tumble. Just my perspective on this. I often wondered if the reason the petrosky stone is localized to the Great Lakes region and not near ocean shores is the wave activity and the softness of the stone. If some seem agatized tumbling might work. Just keep a watch on it.
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hello its mike i just started my pre polish on my petoskey stones i did what you all said and that seams to work fine i left them in 14 houres with 300 then went to 400 ...14h. then 600. 14h. not done yet but they sure look prety good.... ;D thanks for all the help. ......mike
amanda1982: Hi there my daughter wants to get into rock tumbling she is 7 . So I was wanting to find some information here and other websites can anyone give me some recommendation as to where I should look? Also new to this site so have not looked a bunch on here yet
Aug 26, 2014 12:46:34 GMT -5
mr.mohs: welcome amanda1982 RTH is an excellent source with very helpful people especially with a child starting...
Aug 26, 2014 13:00:17 GMT -5
Fossilman: As seen the blast zone on the maps they show,if and when Yellowstone blows is a southern zone,the east and west will suffer some,but not as bad as the southern states...About like Mount St. Helen did...
Aug 26, 2014 13:26:26 GMT -5
Shotgunner: meh.. unless it's truly cataclysmic and the sky darkens so long food wont grow...
Aug 26, 2014 15:29:33 GMT -5
Shotgunner: amanda1982 welcome to the sight. You walk with giants here and there is tons of reading to do. Get to work!
Aug 26, 2014 15:30:05 GMT -5
rockpickerforever: Ed's probably right, SoCal will be underwater by then. Global warming, ya know? My understanding on the ash cloud, it'll come full circle around the plant in no time at all. Just move to Montana now for a front row seat, and get it over with!
Aug 26, 2014 16:35:37 GMT -5
amanda1982: Wow been browsing and there is soooo much info. Now to figure out where to start and which machine to purchase. I wish I had a store close to go and look at the products. Online can be overwhelming sometimes
Aug 26, 2014 17:04:02 GMT -5
mr.mohs: amanda1982 be sure to post an introduction and your question in the VISITOR & GUEST section. I'm sure RTH will be one stop source of invaluable info
Aug 26, 2014 20:46:37 GMT -5
mr.mohs: I was jus think that super volcano would be such cataclysmic advent on the earth vunerable area would slide into the sea
Aug 26, 2014 20:48:02 GMT -5
nowyo: Probably not, Ed, the faults in CA aren't working that way. SoCal will continue it's slow march to the NW and become an offshore chain of islands in oh, 20 or 30 million years. If/when Yellowstone caldera blows we'll have time to say "oh s$#@.
Aug 26, 2014 22:12:02 GMT -5
mr.mohs: so if that sucker blows... none of us will be around to gloat : see I told you so?
Aug 27, 2014 1:02:50 GMT -5
arago: Hey Jugglerguy, I just followed your directions and am washing my rocks (for the first time ever!)in Dawn. Next comes the Borax...
Aug 27, 2014 20:34:48 GMT -5
arago: Wait, what? Did I just jump into a super volcano blow in Yellowstone and a tectonic drift discussion? [pours another glass of Cabernet...]
Aug 27, 2014 20:37:03 GMT -5
arago: Like I said, newb is trying to wash off the residue from his first tumbler run.
Aug 27, 2014 20:38:28 GMT -5
arago: Back to the discussion.
Aug 27, 2014 20:38:44 GMT -5
Fossilman: amanda1982....Go to Kingsley North.com,they are full of goodies and its a one stop store for all your tumbling and hounding needs...
Aug 28, 2014 8:54:45 GMT -5
catmandewe: The volcano at yellowstone finally blew?
Aug 28, 2014 15:29:49 GMT -5
rockpickerforever: Tony, if it did, I think you'd already know about it... Maybe next week.
Aug 28, 2014 15:47:51 GMT -5
Fossilman: Na',it just farted......That place has been burpin' for years though...I think we are lucky it has...
Aug 28, 2014 17:07:55 GMT -5
Fossilman: Would love to see what's underneath that place!!!!!!
Aug 28, 2014 17:08:34 GMT -5