Prov
starting to spend too much on rocks
Member since March 2020
Posts: 116
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Post by Prov on Dec 29, 2020 19:01:07 GMT -5
So after my last big win with the banded amethysts, my wife and I chose some new material, she chose Kambaba jasper (which I screwed up unfortunately, I'll be rerunning them through stages to see if I can correct it). I chose Turritella agate. I did my research, found out it could be a tricky material. I did buy my material blind, and some pieces were pure garbage, but I expected that given the nature of the stone and what it actually is, so I ordered extra. The clean outs were time consuming, but I assured myself that end product would be worth it. I was pretty iffy on moving some of the pieces along, but decided I kinda had to, and just gave it my best to make sure they weren't trapping grit. I am pleased to say, that these came out really well. They also helped me track down my issue with my previous tumbles to adding too much sugar. But that's not what you're here for. You guys want the pictures. I especially like the flat one with the shell ridging on it, and the one with the almost geodey inner shell. There were definitely some pretty cool pieces in it.
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quartzilla
Cave Dweller
Member since April 2020
Posts: 1,237
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Post by quartzilla on Dec 29, 2020 21:36:58 GMT -5
Great job. I can see how that material could be difficult. I would imagine first seeing the rough could be distressing lol.
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Post by jasoninsd on Dec 29, 2020 21:53:00 GMT -5
My favorite is the 5th picture. I'm amazed at how similar some of the shells look like rattlesnake rattles! I just picked up a BUNCH of Turritella and slabbed quite a bit of it this last weekend. I'll be cabbing most of it, but I'm guessing I'm going to get some rough for tumbling out of all of it as well. I'm totally enamored with this material! And, funny enough, I just cabbed my first piece of Kambaba Jasper the other day. I love the tones in that jasper...both you and your wife have GREAT tastes in material!
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Prov
starting to spend too much on rocks
Member since March 2020
Posts: 116
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Post by Prov on Dec 29, 2020 23:35:24 GMT -5
Yeah, I actually have a little rough left - And I see a few pieces I should have put in. Oh well. Edit: I should also add that during the coarse grit step this stuff really wanted to become gravel.
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Post by jasoninsd on Dec 30, 2020 1:06:13 GMT -5
That's what I'm a bit leery of when it comes time to tumble it...pieces chunking off. I have Turritella from two different sources. The other day I slabbed material that matches the darker tones in your stuff. And just as it was getting too dark to cut (it's been too cold since then) the mail arrived with two more pieces of Turritella. The stuff I haven't cut into slabs yet is more yellow and appears to be a lot more dense than the brown. So, I'm excited to see if it might hold up better than the darker stuff. It isn't like the dark brown stuff is "brittle" all over, just along the outside edges it seems on my stuff...which is to be totally expected as that's the part which has been exposed to the elements.
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kyoti
has rocks in the head
Member since June 2020
Posts: 542
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Post by kyoti on Dec 30, 2020 9:44:17 GMT -5
Those came out really well Prov ! Makes me want to try running a batch of my local fossil chert.
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Post by Bob on Dec 30, 2020 10:46:17 GMT -5
They look nice! I have never tumbled a whole barrel full of it, but have tried maybe 20 pieces including one that was small lemon size. It eventually was almost gone because I kept trying to get past voids and cracks. At most I now have maybe 4-5 pieces that polished decently but none as large as quarter.
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Post by jasoninsd on Dec 30, 2020 10:52:23 GMT -5
They look nice! I have never tumbled a whole barrel full of it, but have tried maybe 20 pieces including one that was small lemon size. It eventually was almost gone because I kept trying to get past voids and cracks. At most I now have maybe 4-5 pieces that polished decently but none as large as quarter. That's good information to know. Thanks for chiming in on this Bob. I know I love the looks of this material...and maybe the best bet (for me) is to slab it and cab it rather than trying to tumble some of it...
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Post by Bob on Dec 30, 2020 11:59:59 GMT -5
Jason, I love the look of it also. As I'm sure you know it's not an agate, but petrified organic material. The shells are from the snail Elimia tenera (erroneously originally thought Turritella). I have a rather large piece, maybe 4-5", that was found in the back of some old dusty rock shop a few years ago. It looks tight, so when I work up the courage to try it we'll see what happens. There is nothing more irritating than a gorgeous piece of it that just keeps opening up a porous area just when you think it's ready for the finer grits.
There is a technique involving diluting the clear lapidary epoxy we all probably use, with acetone, and soaking a long time to fill voids in porous material. I have kept a number of articles about this method. It takes 4-6 weeks to do completely, so is a royal pain. But, I'm tried of trying over and over to tumble ocean jasper and having void after void never ending. I've got a piece of that grapefruit size that is gorgeous. I bought a pint of acetone recently and am going to finally tackle this method and see how it goes in some kind of test on a small piece of something porous. It if goes well, I will soak that large piece of turritella in it also before I tumble it.
It seems weird to me that diluting epoxy so much--that it becomes a thin enough liquid to penetrate porous material--that it could afterward "reform" as a solid epoxy again to make this work. The acetone will evaporate readily of course, but it seems that it would leave behind not a solid material but something less than solid because after all the epoxy when diluted was partly acetone. So I'm a bit worried that maybe this method fills in porous areas enough for hand polishing of finished cabs and such but may not be hard enough to withstand rotary tumbling.
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Post by jasoninsd on Dec 30, 2020 13:14:20 GMT -5
Jason, I love the look of it also. As I'm sure you know it's not an agate, but petrified organic material. The shells are from the snail Elimia tenera (erroneously originally thought Turritella). I have a rather large piece, maybe 4-5", that was found in the back of some old dusty rock shop a few years ago. It looks tight, so when I work up the courage to try it we'll see what happens. There is nothing more irritating than a gorgeous piece of it that just keeps opening up a porous area just when you think it's ready for the finer grits. There is a technique involving diluting the clear lapidary epoxy we all probably use, with acetone, and soaking a long time to fill voids in porous material. I have kept a number of articles about this method. It takes 4-6 weeks to do completely, so is a royal pain. But, I'm tried of trying over and over to tumble ocean jasper and having void after void never ending. I've got a piece of that grapefruit size that is gorgeous. I bought a pint of acetone recently and am going to finally tackle this method and see how it goes in some kind of test on a small piece of something porous. It if goes well, I will soak that large piece of turritella in it also before I tumble it. It seems weird to me that diluting epoxy so much--that it becomes a thin enough liquid to penetrate porous material--that it could afterward "reform" as a solid epoxy again to make this work. The acetone will evaporate readily of course, but it seems that it would leave behind not a solid material but something less than solid because after all the epoxy when diluted was partly acetone. So I'm a bit worried that maybe this method fills in porous areas enough for hand polishing of finished cabs and such but may not be hard enough to withstand rotary tumbling. I was searching for threads on stabilizing rocks and found there are a couple threads on here that talk about HXTAL NYL-1 Epoxy Adhesive and actually vacuum-sealing it into the rocks. Tommy even made a home-made vacu-sealer. Might be worth searching that thread out...if I remember right, the HXTAL was "thinner" than the epoxy...and seemed to seep into the rock better...
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Post by Bob on Dec 30, 2020 16:05:49 GMT -5
I have read those also, but don't want to get into anything that complicated.
I've actually had pretty good luck with Epoxy 330. Years were spent by me battling superglue. An example would be a grape size rock, with a pit 1mm in diameter and 2mm deep. Or maybe a slight crack. I would do superglue about as perfect as I thought possible. Then after another week in 220 or 600 or even polish it would be gone! I would think it was my fault, not enough cushioning or whatever. But more or less, I have given up on superglue and tumbling. Even tried different brands and different viscosities but still no luck. About the only time I still use it is in the 2nd week of polish if a tiny pit is visible or same in burnish. It often stays then. Or even after burnish.
Now I set aside rocks in a "need repairs" box. That means Epoxy 330. I've gotten to where I can use the very tip of a toothpick to push it in a tiny hole. If it stays, it will usually stay the rest of the process all the way through polish and look good. But if it doesn't stay, I don't try it again and give up. Discard the rock or saw it or accept it with the pit. Only in last year, have I resigned myself to keeping in my finished material some rocks with little pits. I won't keep them if the pit is on the edge, but if in the middle of a side I might if I really like the rock. But I'm so crazy that at times I will have a tiny pit open in 600 and I'll start all over with it and spend 3 more months taking it back to 220 or larger to get that rock perfect.
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Dec 30, 2020 20:52:34 GMT -5
That looks great! I agree with the others about the 5th one. It's such a fascinating material and one that I look forward to working with someday. The results look like they are worth the frustrations of dealing with a tricky material.
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Post by jasoninsd on Dec 31, 2020 22:30:12 GMT -5
Prov - definitely not trying to hijack the thread. I hope you think this is all relative... I cut a couple more slabs of Turritella this afternoon. I find the differences amongst the three slabs are pretty amazing. One slab is similar to the OP's colors...dark matrix with light colored Turritella. Another slab has the dark matrix, but the Turritella are a more golden yellow. The big slab is more of a golden colored matrix, the Turritella are smaller and fewer, and the slab seems a lot more dense (less crumbly) than the darker colored matrix slabs...I've been calling this my blonde Turritella. LOL
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Prov
starting to spend too much on rocks
Member since March 2020
Posts: 116
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Post by Prov on Jan 3, 2021 17:48:09 GMT -5
jasoninsd No worries man, this is very interesting to read. Your blonde Turritella looks pretty neat too! I'm more partial to the darker colors. One of these days, I'm interested in getting into slabbing, but I'm waiting for covid to blow over before I join my local rock club. For now tumbling is working out for me!
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Post by jasoninsd on Jan 3, 2021 19:41:08 GMT -5
jasoninsd No worries man, this is very interesting to read. Your blonde Turritella looks pretty neat too! I'm more partial to the darker colors. One of these days, I'm interested in getting into slabbing, but I'm waiting for covid to blow over before I join my local rock club. For now tumbling is working out for me! I cut some preforms out of that "blonde" slab and I have to take back what I said about it seeming more dense. It actually now appears to be a bit more crumbly than the darker material. I second your opinion on the darker colored matrix. I too like it better, as the contrast of the dark matrix with the lighter Turritella just really catches my eye.
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