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.
In the beginning was the Floyd, and the Floyd was with Him, and He was with the Floyd. Syd Barret just disappeared, right after the happening. Lita Ford drives a suburban! Big Hair Heavy Metal is dead. Oh weeping and gnashing of teeth, the end is near. The answer is 42. 42! BING! BIG BING!
Follow the White Rabbit!
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
rockpickerforever: Wishing you and your son the best, Jim. Jean
Jul 25, 2014 15:31:05 GMT -5
1mofo: I'm new to this page how do you post something or ask for tips or help ?
Jul 26, 2014 19:25:28 GMT -5
catmandewe: you just did
Jul 26, 2014 21:24:10 GMT -5
linus: bobby1: I placed a message for you to ask for a copyright. Please read my message since I know no other way to contact you.
Jul 27, 2014 5:37:07 GMT -5
drocknut: Jim, sending prayers for your son and your family.
Jul 27, 2014 16:16:20 GMT -5
snowmom: Good morning! 50 degrees here with the wind from the NW, leaves rustling and it makes me restless... the rocky beaches will be in full song this morning. Think I'll take my camera and take some pics this morning for show and tell. what are you all up to?
Jul 28, 2014 5:24:08 GMT -5
wampidy: Sitting in my underwear in front of the computer drinking cappuccino and eating brown sugar and cinnamon pop tarts. A mental image you probably could have went without but you asked. Want to go hounding, all gassed up but I gotta buy some new tires for my
Jul 28, 2014 5:58:04 GMT -5
wampidy: pickup before I go running around in the hills. One of my goodest tires has a bulge and all the tread is worn off of it in that spot. Tells me that I probably should have replaced it a long time ago but it is just a little wup wup.
Jul 28, 2014 6:01:01 GMT -5
snowmom: LOL, I did ask.. I'll be more careful next time! I expect hounding out there is a terror on tires- all those sharp rocks...
Jul 28, 2014 6:12:29 GMT -5
drocknut: Snowmom at least he didn't say he was naked...;)
Jul 28, 2014 18:42:15 GMT -5
rockpickerforever: Diane, if he said he was sitting in his underwear, most would understand that he is not naked. What's wrong with naked, anyway? ...Unless that's your laptop sitting in his lap, ho ho!
Jul 28, 2014 20:08:31 GMT -5
rockpickerforever: Ouch! Ha ha, gotta at least wear some leather chaps! How're you dune, Ed, out in that furnace they call Phoenix? Grinding and sweating? Mostly? You do what it takes...
Jul 29, 2014 0:58:51 GMT -5
mr.mohs: grinding naked...best way to get a buff on stone
Jul 29, 2014 9:39:27 GMT -5
mr.mohs: howdy Jean - doing a mild summer- that's two in a row- Phoenix is the best weather in the country-another few weeks and I'll be scantily dressed & in full rock'n heart production...take care..Ed
Jul 29, 2014 9:42:35 GMT -5
wampidy: There was not one of the tires on my pickup good enough to replace my raggedy spare. Just went ahead and bought all four. As bad as the front tires were it is a wonder I am not laying in a ditch somewhere between here and Quartzsite.
Jul 29, 2014 23:23:50 GMT -5
wampidy: Sure drives nice now except for the wandering. Replaced the steering ball joints before I left for Q and they already have a bunch of slop in them. Must have been a tad bit of stress there on the trip.
Jul 29, 2014 23:27:08 GMT -5
Fossilman: New tires are always a blessing...
Jul 30, 2014 8:54:32 GMT -5
snowmom: we just got new tires too.. must be the season... or maybe the places we go? Yes,a blessing... the difference is amazing, and the car actually stays on the road in the rain now...
Jul 30, 2014 17:52:22 GMT -5