Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Sept 26, 2012 1:49:50 GMT -5
Hi All,
I just got several pieces of limonite, and will love to tumble them. Have anyone done it successfully? I haven't seen any pictures of them tumbled, I wonder why. My plan is to shape them first with a dremel and then to the tumbler. Any advice or tips on the best ways to do it will be appreciated.
Thanks,
Dora
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Sept 26, 2012 2:34:42 GMT -5
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Post by geoff on Sept 26, 2012 2:37:49 GMT -5
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Sept 26, 2012 4:04:22 GMT -5
I did some tumbling in the past and I’m coming back to it with the desire to try to tumble the stones that I can’t buy tumbled already (I’m a collector of tumbled stones). The softest stone I tumbled was a Larimar (mohs 5-7), and because I only had a small piece I was very careful with it. I did the first 2 stages with the dremel and then placed it in the pre-polish, polish and burnishing stages and came out pretty good. I tumbled it with some feldspar and used ceramic pellets in the pre-polish and plastic pellets the rest of the way. I was thinking of using a similar technique with the Limonite. By your replies I really think it is probably either extremely hard or actually impossible. So as a learning experience (if I don’t get any more tips) I will only try it with a few small pieces in a small 1.5 lb. capacity barrel, and save the others for the future or polish them with my dremel. I appreciate your replies, thanks Dora
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Post by NatureNut on Sept 26, 2012 7:04:21 GMT -5
Hi Dora, If you're gonna try it, I would suggest starting at prepolish (500 grit) with lots and lots of cushion. Do not put in anything harder than the stone. Try pieces of rubber or felt or leather. Don't expect a shine, just a matte finish. Expect that your pieces will wear down lots so don't put in too small pieces of your stones. Try a little sliver of Dove or Ivory soap in the barrel too to help them slide. That's my best advice. Good luck and keep us posted. Jo
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Post by Hard Rock Cafe on Sept 26, 2012 11:42:04 GMT -5
I'm no help, but Lakers frequently have limonite and I usually try to grind it off! Chuck
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Sept 26, 2012 12:19:51 GMT -5
Thanks Jo, I never tried using pieces of rubber, felt or leather, sounds like a good thing to try. My expectations are quite low on shine but smoothness and shape will make me happy. I really need to get some experience with softer rocks so this will be quite a challenge with nothing valuable to lose.
I was thinking to start the pre-polish with SISA (Don't know grit size) and then polish them with tin oxide. I currently have SISA and Tripoli (pre-polish) but they don't specify their grit size. I also have Aluminum Oxide 1000 grit that could be used as well. For the polish stage I have several to choose from but the one that worked well with my Larimar & feldspar stones was Tin oxide, so I was thinking of trying it first. I was using Borax for burnishing but will try your soap suggestion instead because the thicker and slippery consistency makes a lot more sense. If I figure out how to post pictures I will show the end results after I finish it.
Great tips, thanks!
Dora
PS. Thanks Chuck, I will certainly grind some off! ;D
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Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
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Post by Minnesota Daniel on Sept 27, 2012 18:33:56 GMT -5
Limonite is a generic term for an amorphous mixture of iron oxides and hydroxides, so its hardness is variable too. As Chuck said, the stuff that coats Lakers seems to be as hard as the Laker itself. I suspect though that "Laker Limonite" is actually partially silicified limonite. You probably have limonite iron ore, which isn't consistently solid. My guess is that it won't polish at all, but it can't hurt to try.
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Sept 28, 2012 3:54:08 GMT -5
Actually I'm having a really hard time trying to cut them with my dremel diamond wheel, never had that amazing fireworks experience before. I tried testing them with a quartz (to find out their actual hardness) and the line marks totally disappeared when I rubbed my finger over them. I will try grinding them to size to see if that works better. Their color is mostly chocolate brown (like a Hershey's bar) with some darker parts. Some parts are dull and some have some luster when placed near light. Perhaps the limonites I have are the same ones pestering the lakers. Sorry I have no pictures. I found out how to post pictures but still have to create a photobucket account, when I have the chance. Your post was very useful, thanks Daniel. Dora
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Sept 29, 2012 23:37:11 GMT -5
I spend hours grinding and rounding one of the pieces of limonite with my Dremel. I was really surprised to find out that it actually shines and once polished I think (and hope) it will look very nice. I believe that it could be tumbled as well and will probably start it tomorrow, if I have the time. The main problem I had was that it stained my hands and fingernails brown, and it was really hard to remove those stains… I don’t know how long it will take me to tumble them, but I will post the final outcome when the time comes. Thanks again to all for your helpful support. Dora P.S. I learn many interesting things about the many uses of Limonite in the link below. Limonite seems to be an amazing rock! limonitemalaysia.com/what_is_limonite.html---------------------------------------------------------------------------- The first photo shows the rough rocks with the rounded semi-rough that I did today. The second photo is with a flash to try to show where they shine.
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