karldubya
starting to shine!
Member since March 2021
Posts: 32
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Post by karldubya on Apr 10, 2021 14:43:11 GMT -5
I’m not sure what this is? Found it rock hunting on Lake Huron halfway up Michigan thumb. It’s heavily pitted so probably won’t polish well anyway, and I’d be afraid of losing the crystallized part.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Apr 10, 2021 14:50:06 GMT -5
You'd lose the crystalline part. I'm still toying around with figuring out an epoxy to use to fill vugs for tumbling and dissolve after with acetone or something.
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rockstock
spending too much on rocks
Member since April 2019
Posts: 472
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Post by rockstock on Apr 10, 2021 15:19:57 GMT -5
Reminds me of this Michigan one I found as well. Agatized fossil, partially.
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Post by manofglass on Apr 10, 2021 15:29:17 GMT -5
You'd lose the crystalline part. I'm still toying around with figuring out an epoxy to use to fill vugs for tumbling and dissolve after with acetone or something. See if this will work kingsleynorth.com/attack.html
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Apr 10, 2021 15:46:43 GMT -5
Interesting... It's a mixture of dichloromethane and dimethylformamide as a proprietary blend. Going to need some good gloves. DCM and DMF have short breakthrough times.
Thanks for that tip. I wasn't aware the average person could get their hands on that so easily.
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Post by stephan on Apr 10, 2021 19:53:12 GMT -5
Interesting... It's a mixture of dichloromethane and dimethylformamide as a proprietary blend. Going to need some good gloves. DCM and DMF have short breakthrough times. Thanks for that tip. I wasn't aware the average person could get their hands on that so easily. PVA, butyl rubber, neoprene or viton gloves do better than most. Both of these chemical are carcinogenic through both the respiratory and dermal routes. If you cannot use them outside, strongly consider a respirator (this coming from the guy who says respirators are rarely necessary when cabbing). DCM is also known as methylene chloride.
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lparsons
Cave Dweller
Member since April 2020
Posts: 276
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Post by lparsons on Apr 10, 2021 20:26:37 GMT -5
I’m not sure what this is? Found it rock hunting on Lake Huron halfway up Michigan thumb. It’s heavily pitted so probably won’t polish well anyway, and I’d be afraid of losing the crystallized part. Personally I don’t think I’d tumble it. I think it’s pretty neat just like it is.🤗
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Post by aDave on Apr 10, 2021 20:51:08 GMT -5
I’m not sure what this is? Found it rock hunting on Lake Huron halfway up Michigan thumb. It’s heavily pitted so probably won’t polish well anyway, and I’d be afraid of losing the crystallized part. Just keep in mind that pitting has no effect on whether or not a rock will polish. It's the hardness that makes a difference. If that rock was hard enough to take a polish, pitting or other imperfections really don't mean a lot. The issue is whether or not the hardness will allow for a polish. I'm going to guess the outside layer is too soft and won't polish. As such, you'll have to really grind down this rock past the matrix. The lower layer looks like it might take a polish, but you'll lose an awful lot by trying to get there. With that, you'll probably lose the crystalline formation you see. So, your decision is based on whether or not you want to save the crystals. If you want to save them, don't tumble. If you don't care, go ahead and throw the rock into the tumbler. The outside skin may be removed, and you'll be left with something different than what you're dealing with now.
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Post by Bob on Apr 13, 2021 13:57:58 GMT -5
I have tumbled rocks like that, with the interior being non-solid quartz, and results have been 95% disappointing, so I don't bother anymore. Now and then a whole lot of different kinds of rocks will have a quartzy region like that. That place almost always remains slightly fractured or porous or problematic in some way. I have a few agates with centers like that that I've kept going and going hoping it would eventually be more and more solid in that area, but mostly it's just been a waste of time.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Apr 22, 2021 15:23:08 GMT -5
It’s quartz and chalcedony replacing a fossil coral, in soft limestone matrix. Not suitable for tumbling. Might polish on a cabbing machine. Some of these make interesting cabs.
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Post by rmf on Apr 22, 2021 18:28:57 GMT -5
Fill the crystal vug with epoxy and tumble. Once polished drop in acetone and take the epoxy out.
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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 May 4, 2021 7:21:17 GMT -5
Looks like a lamprey eel fossil. They have that same sort of mouth opening. Or just a piece of quartz.
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Post by Bob on May 5, 2021 11:11:29 GMT -5
OMG I actually had the same thought at one moment, though it passed because I knew it couldn't be one. Really enjoyed that video! As someone who used to maintain a university's zoological museum, which had a huge alcohol specimen collection, I had inspected the formidable mouth of this species. I was very nervous as to what might happen. I had no clue that they would avoid his skin like that.
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Post by broseph82 on May 6, 2021 18:03:22 GMT -5
I’m not sure what this is? Found it rock hunting on Lake Huron halfway up Michigan thumb. It’s heavily pitted so probably won’t polish well anyway, and I’d be afraid of losing the crystallized part. I tumble stuff like this all the time. More than likely you will NOT lose the crystals but may get a piece of ceramic stuck/wedged in there from pre polish/polish stage.
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ujean
off to a rocking start
Member since September 2020
Posts: 3
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Post by ujean on May 10, 2021 17:46:51 GMT -5
Since majority of the replies say not to tumble. What would be the best way to “polish” that rock by hand ? Or dremel?
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