I have been given four geodes (those hollow rocks with pretty crystals inside) the smallest about 3-4 inches to about 8-10 inches. Me being a carpenter if they were made out of wood I’d have no problem cutting them open. So I’m asking for help from you stone masons. Is there a way for me to cut and polish them or should I seek professional help (to cut the stones, I already know I need help). So what say you, is there a way for me to clamp and cut with a masonry blade on my table saw. Or maybe a tile saw??? Bill D.
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My 10" tile saw has a max depth of 3 1/4", so I'm guessing you'd need a really big tile saw.
A diamond blade on a 4 1/4" angle grinder might do the trick, depending on how thick the shell is.
Diamond blade on your table saw? Hmmm... now that's an interesting proposition. Not sure how good the dust will be for your saw.
See my work at TedsCarpentry.com
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I cut and polished several geodes back in college days when taking a geology course. The saw was similar to a tile saw. You had to go slowly in case you found a weak section that might make the whole thing crumble. To polish we had a machine with a large plate that vibrated. You put a slurry of water and emmory powder on the plate and left the machine go for several days, changing to finer grits every 24 hrs or so. I'm guessing this isn't possible to do by hand. Any local rock hound shops in your area? They'd be able to help
Short answer, no!
very special equipment to have it come out nice and all too easy to ruin if done wrong.
Nearly every major town has someplace that cuts stone.. grave stones, commerical buildings, etc.. look in the yellow pages for stone cutters..
Having said that I've cut enough stone so I would feel confident renting a masonary saw at a rental center and attacking them.. But for a first time cut into a geode? Too big a risk!
Remember those agot quartz belt buckles back in the '70s? Or maybe I'm a little more redneck than some folks here =). But there was a guy in my neighborhood who cut and polished them with just basic tools. I didn't know the guy or what tools he used, but trust me when I say he couldn't afford anything fancy. So I'm guessing the geodes can be cut and polished at home by someone with a little imagination.
The polishing part could be done with emory cloth and a flat surface.
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Edited 12/20/2008 10:24 am by Ted W.
Easy
Look for a lapidary supply store. They sell rocks and usually setting, chains all sorts of grinding and polishing supplies. They will have a diamond saw of know who has one.
They cut with water and can have blades 20 inches or more. They cut slow and leave a finish that takes awhile to make shine. The flat thing is called a lap. they viberate or the the old days go round and round. changing grits finer as said. Been a few years but I believe you need to get to about a 1000 grit to get a good polish and then they use an oxide finish for the final polish.
Probably faster to farm it out that try. If you try a blade that may wiggle you might get parts of blade/rock flying around. The geodes are an agate and about 7 on the hardness scale of 10. they may have some internal cracks. But the beauty inside is worth the trouble. No one is the same and you never know what you are going to find.
Good luck
BB
OK...OK, I guess I'll stick to making sawdust. It was just a thought, tho I REALLY am curious to look inside, one rattles when you shake it.
With the tablesaw I was going to rely on the shop dust collection system. BUT, a local tile guy here says the "dry" blade would be a bad idea, too fast, too hot, etc. So I guess I'll wait to find a local stone cutter. I do know of one but , he was in an accident awhile back and last I heard wasn't doing well, still in therapy. Man he was good. Build a few stone fireplace/chimmneies for me with locl field stone. Beautiful work. The kinda guy that could carve birds in flight up a granite chimney face.
Anyways thanks to all for your advice. Merry Christmas and Happy Holidays to all
Bill D. Quality Wood Chips
P.S.
"Lil Chip" says have a Merry Spirit too!
Edited 12/20/2008 10:46 am ET by billy5151
I'd consider trying cutting just one with a minigrinder and a diamond blade. If possible, have someone hold a hose so water drips on the stone while your cutting.
You can polish it with wet/dry silicon carbide sandpaper. Since silicon carbide is second in hardness to diamond, it'll cut the geode, which I think is quartz of some kind. But I would imagine that polishing by hand would be very slow going.
I think the big question shouldn't be whether it can be cut with basic tools, but how nice and perfect the cut has to be. There is no rule saying the cut has to be a perfect slice. If polished up, I think a less than perfect cut would look even better than perfection. I mean after all, it's a rock. Perfection is way overrated and sometimes tends to take all the fun out of things.See my work at TedsCarpentry.comBuy Cheap Tools! BuildersTools.net
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