doublebluff
having dreams about rocks
Member since September 2021
Posts: 60
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Post by doublebluff on Oct 4, 2021 22:10:16 GMT -5
Thank you for the welcomes on my introductory post. Now, the questions that led me to this forum: First, I find agates that have a nice section that I might not want to polish- mainly indentations or surfaces that have the crystals remaining from development of the agate (as I understand it). Here are a few examples. Is there any way to protect the crystalline structure during the tumbling process, such that the outside of the rock would get polished and the crevice with the crystals would be untouched? I am envisioning some kind of liquid polymer that hardens into a tumble-resistant layer that you could coat the area you don’t want to get polished and could remove with solvent after the tumbling is done. Next, I found a rock the other day which has an interesting structure within. You can see the dime-diameter circle in this picture, found on both sides, almost like a petrified stick inside the rock. What type of rock might this be, and what might the internal structure be?
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Post by Pat on Oct 4, 2021 22:29:37 GMT -5
Your second photo could be a bone in matrix. I’ve seen several of those.
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quartzilla
Cave Dweller
Member since April 2020
Posts: 1,237
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Post by quartzilla on Oct 5, 2021 7:51:37 GMT -5
There is a topic on here somewhere about using various epoxies and other substances to fill in voids to keep the druzy parts. Not sure if those techniques would work with the stones you have pictured. The voids are pretty large on the 2 on the right; that would be a huge blob of filler that I imagine would be difficult to keep in place while the rest of the stone polishes. Most stones I’ve seen that have the druzy parts intact are smaller voided akin to a porthole or a small window .
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quartzilla
Cave Dweller
Member since April 2020
Posts: 1,237
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Post by quartzilla on Oct 5, 2021 7:52:30 GMT -5
By the way where do you live that you find so much agate material?
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gatorflash1
spending too much on rocks
Active in Delaware Mineralogical Society, Cabchon Grinding and Polishing, 2 Thumlers B's and a UV-18
Member since October 2018
Posts: 375
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Post by gatorflash1 on Oct 5, 2021 13:50:34 GMT -5
I don't waste time trying to tumble stones with lots of pits, crevices, etc. I stick with good stuff that will grind out with clear, clean surfaces in step 1. Try red jasper. Here's a good book for all newby tumblers. rocktumbler.com/book.shtml
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doublebluff
having dreams about rocks
Member since September 2021
Posts: 60
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Post by doublebluff on Oct 5, 2021 21:07:43 GMT -5
Thanks for the ideas. I will check on the resin. Jasper is very cool- my wife likes it better. But, I still like tumbling my crystal-containing agates!
I pick agates in gravel piles on western Oregon riverbanks.
The bone idea is fascinating. I will add that I accidentally put the same pic twice in my post- I just changed that and included a pic of the other side of the rock.
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Post by holajonathan on Oct 6, 2021 10:40:32 GMT -5
Thanks for the ideas. I will check on the resin. Jasper is very cool- my wife likes it better. But, I still like tumbling my crystal-containing agates! I pick agates in gravel piles on western Oregon riverbanks. The bone idea is fascinating. I will add that I accidentally put the same pic twice in my post- I just changed that and included a pic of the other side of the rock. Two thumbs up on your desire to tumble the rocks you found! The results will not always be as flawless, but it is quite satisfying -- more so than tumbling commercially bought rough, in my experience. As you can see here, I have tumbled anything and everything I found locally, even though I don't live in a good area for finding rocks. forum.rocktumblinghobby.com/thread/93989/mediocre-michigan-rocks-niceUnfortunately, I have no good advice on preserving crystals when tumbling.
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Post by Peruano on Oct 6, 2021 14:49:55 GMT -5
If it was me with your goal, I'd do a it of clean up on the outside of the stones with a diamond or sic wheel, and then toss them into a vibratory tumbler or minisonic. In my experience a lot of crystals that I expected to go away, survived the much gentler treatment of a vibe. It goes to figure, 7 - 9 days in a vibe is much gentler than weeks/months in a rotary.
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Post by Bob on Oct 6, 2021 16:03:01 GMT -5
No idea about that pattern in that one rock, though I like the rock.
On the protection of the crystallin cavities, I can't think of anything that could withstand the tumbling yet also be removable later. You could get into hand grinding and polishing I suppose and just work around such areas.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Oct 7, 2021 21:15:24 GMT -5
If you want to save a bit of drusy, grind and polish your rock on a cabbing machine. Will take under an hour. Your rock looks like a type of breccia, basically a rock that has been broken, moved, and cemented together.
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