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
rockpickerforever: Supposed to get cold and windy here, couple inches of rain forecast for the weekend, and then some. Even the desert is supposed to get liquid sunshine. We need it, but why can't it rain during the week? So much the for the rock field trip this weekend.
Feb 26, 2015 11:00:52 GMT -5
rockpickerforever: Fossilman, making a nice hot batch of the Jalapeno jelly today, yum!! Can't get enough of that stuff! Might go out and use the stove in the trailer, so I'm not breathing chile pepper fumes all day, lol.
Feb 26, 2015 11:04:07 GMT -5
rockpickerforever: Oh, I should mention... Cold here is maybe down into the 40s. Not that below freezing or below 0 type of insanity. Who can live in such a place that has those temps? And all that white stuff, uggghhhh!
Feb 26, 2015 11:11:22 GMT -5
drocknut: Chili pepper fumes, one way to clear out the sinuses..lol. I can handle the cold (btw 40 doesn't count as cold yet) but that hot stuff you call jelly geez how can you eat that...lol.
Feb 26, 2015 12:16:47 GMT -5
rockpickerforever: Diane, it's not the sinuses, the fumes make you gag and your throat burn. Trying to be considerate of poor, sick Lucy. Diane, you just don't know what you're missin. And yes, considering what it costs to live here, 40 degrees IS damn cold, lol.
Feb 26, 2015 12:42:17 GMT -5
edmohs: I'll just be grinding in the rain this weekend. And if you heard my singing it sounds just the same. rain or no rain...mostly
Feb 26, 2015 18:53:11 GMT -5
Fossilman: Tammy just made up a batch of Habanero jelly last week...........Yes,it clears the house for awhile...LOL Love that jelly too...Taking a jar or two to Roy's today..
Feb 27, 2015 10:14:32 GMT -5
rockpickerforever: Fossilman, that jalapeno jelly came out smokin' hot, the hottest batch yet. Close to being too hot, maybe?? The jalapenos give it that great flavor, add about ten Hot Black Cobra chilies for heat. Need to eat it with something to avoid stomach ulcers.
Feb 27, 2015 11:51:10 GMT -5
rockpickerforever: The rain is a'coming. Supposed to get cold, windy and wet tonight, and stay that way until Tuesday. Yep, field trip to Himalaya Mine on Saturday has been postponed... edmohs, okay to sing, mostly, but stay out of the rain! Grind 'em, baby, grind 'em!
Feb 27, 2015 14:37:30 GMT -5
snowmom: baking brownies....
Feb 27, 2015 16:45:55 GMT -5
wampidy: Food with pain has never made a lick of sense to me. Brownies sound good.
Feb 27, 2015 18:48:39 GMT -5
Rockoonz: Our rock club lapidary shop is now in a building with lots of handcrafters and artists, across the hall is Honey Mamas organic fudge, sweetened with honey. My favorite has cayenne in it.
Feb 28, 2015 1:53:02 GMT -5
rockpickerforever: Jim, ever heard of "hurts so good?" Just kidding. My jalapeño jelly is hot, but not 3-alarm. Snowmom, what kinda brownies did ya make?
Feb 28, 2015 7:20:28 GMT -5
drocknut: Yes I do know what I'm missing Jean, heartburn. ...lol.
Feb 28, 2015 10:36:05 GMT -5
drocknut: Mmmm brownies, mmmmm fudge now I'm getting hungry.
Feb 28, 2015 10:38:13 GMT -5
snowmom: jean, they are plain with powdered sugar on top, son has "bodfl" and ordered them that way.
Feb 28, 2015 11:32:26 GMT -5
snowmom: Bodfl is 'brownies on demand for life' my life or my ability to keep making them. Very few people have bodfl
Feb 28, 2015 11:32:56 GMT -5
snowmom: my other specialty is fudge. nobody has fodfl..
Feb 28, 2015 11:35:10 GMT -5
drocknut: My grandfather made wonderful fudge. We kids got to help him mske it. Fun memories of him.
Feb 28, 2015 12:23:20 GMT -5
Pat: rockpickerforever 's jelly is the best! I make peanut brittle, and peppermint bark. Used to make caramels (yum), but can't handle the butter anymore.
Feb 28, 2015 15:15:23 GMT -5