FossilFamily_24 Posted February 15 Share Posted February 15 (edited) Hello. We are beginners, and have a large concretion (suspected crab). What is recommended for removing the excess rock to expose what’s inside it? We want to minimize damage to it. It sounds as if breaking and freeze/thaw aren’t ideal for opening it. I’ve been trying to learn, but still not certain and feel safest asking. Money is tight this week, but would like to get something to begin on it and upgrade in a couple weeks. Any suggestions? Thank you. (I was thinking a 290 dremel w/fossil bits and later an air tool…uncertain which is best. Actually, I see that is a UK model.) Edited February 15 by FossilFamily_24 1 Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 15 Author Share Posted February 15 Link to comment Share on other sites More sharing options...
Misha Posted February 15 Share Posted February 15 Why do you suspect it's a crab concretion? Usually whenever crabs are found they either have their carapace or underside weathered out or you can see the crossection of the legs/ pincers on the side of the concretion. Here I do not see anything like this. Most concretions don't contain fossils so unless you find some kind of feature suggesting there's something inside, it may be empty. Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 15 Author Share Posted February 15 (edited) It was said to be “suggestive of crab” when I posted on another fossil page asking if it could be a concretion or not. I believe, the replies were going off the pincher type shapes along both sides (they mirror one another in shape, size and appropriate direction, whatever is causing it). We don’t know, however. That is what we’re trying to discover by opening it. Thank you! Edited February 15 by FossilFamily_24 Link to comment Share on other sites More sharing options...
jpc Posted February 15 Share Posted February 15 (edited) This is huge for a crab concretion. Are crabs known form the area where you found this? I doubt there is a crab in there, but there could be many other kinds of fossils. Again, are fossils in concretions known from the area? If not, I would just hit it along the edge with a sledge hammer, rather than searching blindly for a crab. Tap it around the equator a few times then move over a bit, still along the equator, and hit it some more. Keep going around like this until it breaks. Maybe it will break down the middle (along the equator) or maybe not. I am curious to see what others think. Edited February 15 by jpc Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 15 Author Share Posted February 15 (edited) Thank you! (crab wouldn’t be far fetched, but this big is questionable.) Edited February 15 by FossilFamily_24 Link to comment Share on other sites More sharing options...
FossilDAWG Posted February 15 Share Posted February 15 Where was this found? That would have some bearing on the likelihood of it containing a crab. Usually crab concretions are not perfectly round. They tend to be a little wider across where the legs would stick out at the sides, and a little more squared off in front where the claws would be. As well, often they are flatter on top and a bit rounder on the underside, although this may be quite subtle. Unless you want to invest a lot (up to thousands of dollars) in prepping equipment just to explore and see if there is a crab in there, your best bet at the moment might be to try to crack it open as @jpc suggested. If you do that, clean up the area around where you will be working, and consider covering the floor with a tarp before you attack the concretion. The idea is to not lose any bits if the concretion shatters and there is a crab in there. If you have all the bits you can glue them back together and then prep with more precise tools. Don Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 15 Author Share Posted February 15 (edited) Yes, fossils have been found (in & out of concretions), crabs occasionally. I just don’t know about this large. Thank you! Our goal is simply to open it…we will be just as thrilled if it’s a plant. Edited February 15 by FossilFamily_24 Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 15 Author Share Posted February 15 (edited) You can see our attempt at a smaller concretion in my profile. It didn’t go well (chipped and lost a piece of shell). So, I’m simply hoping to do better with this one. Edited February 15 by FossilFamily_24 Link to comment Share on other sites More sharing options...
Fossildude19 Posted February 16 Share Posted February 16 Again, where was this found? County level would be good enough to decipher if crab is an actual possibility. Your profile picture looks more like a bivalve than a crab claw, to me. (IF this is the image you are talking about, that is.) I vote for just giving it some whacks with a small sledge hammer. 1 Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
FossilDAWG Posted February 16 Share Posted February 16 23 minutes ago, Fossildude19 said: Your profile picture looks more like a bivalve than a crab claw, to me. To me as well. The ribs are typical of a bivalve, and would not be found on a crab claw. Don 1 Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 16 Author Share Posted February 16 (edited) The profile picture is of a small opened concretion (one never suspected being a crab). It didn’t go well, and that’s why I’m looking for information before we try on this large one (whom some said could be a crab, potentially). We’re not concerned whether it is or isn’t one, rather the best way to go about working on it (method, tools). I only mention the “suspected crab”, in case it would matter. For instance, I have read freeze/thaw isn’t ideal in that situation. We’re new, clueless and trying to learn. Thank you. Edited February 16 by FossilFamily_24 Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 16 Author Share Posted February 16 This is probably why some thought possibly crab…but not a big deal, just some trying to help when I was asking if it could be a concretion. (The first picture doesn’t show it as well, was just taking a random picture and someone noticed it and asked if the other side looked similar… and it does, so intentionally took a picture of that side to show her.) Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 16 Author Share Posted February 16 I should mention, my teen son simply liked the rock. He brought it home thinking that was all there was to it…just a neat rock. I started questioning if it could be a concretion after the fact and then posted asking about it (different group). Link to comment Share on other sites More sharing options...
SPrice Posted February 16 Share Posted February 16 I would recommend the Dremel 290. For around $20 you get a lotta bang for your buck in beginning fossil prep. The Zoic Dremel stylus kit is a must. Comes from across the pond. Here's the link: https://www.zoicpaleotech.com/products/3-pack-fossil-preparation-styli-long-short-chisel-to-fit-the-dremel-290 Trying to use the original bit in the Dremel is frustrating at best. The bit just thuds along ...like plowing a cornfield with a stick. The Zoic tungsten styli are the best upgrade ever. Air scribes would be the next step. And it's a big step. A much bigger commitment in money, proper set up, noise, electricity usage, etc. i really enjoy my 290 and zoic bits!!! As for another option, I went old school and crafted small chisels from steel punches by annealing them, grinding the business to suit the purpose, then re-heated, quenched and tempered them. I have blacksmithing and stone carving skills so this was an easy, natural fossil prepping tool kit addition. The Dremel has a learning curve like anything new. Shoving, pushing and ramming the bits on the matrix is 100% wrong. Practice on the different matrices scraps to find the right tool setting and right amount of pressure. Surprisingly, the lightest pressure possible at the correct dial setting is the right approach. Slow and steady, take breaks, have the proper safety gear and know that everyone will have a boo-boo on a fossil at some point. Practice on scraps, Practice, practice. Get the feel. It takes a while, but I am improving and can almost intuit where the put the stylus tip and at what angle and amount of pressure ( the lightest touch ) and PING! a matrix chip flies and the fossil is not damaged. That would get you started. The Dremel is an electric micro jack hammer. The air scribes, depending on the model, are the same principle tools but way more efficient, powerful and expensive. One of the main differences is the start to finish time. Several hours with the Dremel on a small easy, soft matrix could be 30 minutes with an air scribe or faster. It's a journey not a race. The tortoise gets the prize, the rabbit gets a mess in this endeavor. My 50 cents. Steve 2 1 Link to comment Share on other sites More sharing options...
citronkitten Posted February 16 Share Posted February 16 1 hour ago, SPrice said: I would recommend the Dremel 290. For around $20 you get a lotta bang for your buck in beginning fossil prep. The Zoic Dremel stylus kit is a must. Comes from across the pond. Here's the link: https://www.zoicpaleotech.com/products/3-pack-fossil-preparation-styli-long-short-chisel-to-fit-the-dremel-290 Trying to use the original bit in the Dremel is frustrating at best. The bit just thuds along ...like plowing a cornfield with a stick. The Zoic tungsten styli are the best upgrade ever. Completely agree regarding the Zoic styli! The upgrade is immediately noticeable. I've been living across the pond for a number of years now, so didn't have to fork out for shipping, but would definitely say they are worth the investment. I was wondering why people even recommended the Dremel engraver tool as the original styli were so useless, but with the different tips it works absolutely as well as people say. Good luck! 1 1 1 Link to comment Share on other sites More sharing options...
Ptychodus04 Posted February 16 Share Posted February 16 I would NOT recommend a Dremel engraver for an attempt to prepare something this large unless you plan to turn this into a very long running endeavor. They are fine for prepping smaller items but they vibrate like mad and tend to overheat (I burned up several as a newb prepper). If you do it, work in short bursts (30 minutes or less) with long breaks between sessions to allow your hand to recover. This being said, we still have no idea if there's anything in this big ole rock and repeated requests for locality info (a must to determine all but the most general info on a fossil) have been fruitless. The close up photos are too blurry to be of real use but look to me simply to be the outer layer of the concretion coming off. I've been prepping fossils for close to 30 years and have all the tools to prep something this large and if it were mine, I would crack it open to resolve the mystery and go from there. If you follow @FossilDAWG's advice and break it on a tarp, even if bits come off, they can be recovered and glued back on. 1 1 4 Regards, Kris Global Paleo Services, LLC https://globalpaleoservices.com http://instagram.com/globalpaleoservices http://instagram.com/kris.howe Link to comment Share on other sites More sharing options...
Jaybot Posted February 16 Share Posted February 16 I use the Dremel 290. You MUST buy yourself vibration absorbing gloves! The vibration can cause nerve damage... permanently. I use gloves made for jackhammer use, here's a pic of ones like mine: 1 1 -Jay ''...science is eminently perfectible, and that each theory has constantly to give way to a fresh one.'' -Journey to the Center of the Earth, Jules Verne Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 16 Author Share Posted February 16 Illinois, but we’re not worried about what’s in it and understand many times nothing is left. In the end, it will be my son’s decision. I just wanted the information to pass on, since what I come up with on my own wasn’t as clear as I had hoped. Thanks, everyone! 1 Link to comment Share on other sites More sharing options...
FossilDAWG Posted February 16 Share Posted February 16 If it's from Illinois, I don't know what is in it except it's not a crab. Marine rocks of the appropriate age (Jurassic to recent) do not occur in Illinois, and no crab concretions have ever been reported from that state. That concretion seems very large for a Mazon Creek type nodule as well, but who knows? Don 1 2 Link to comment Share on other sites More sharing options...
SPrice Posted February 16 Share Posted February 16 On 2/16/2024 at 10:00 AM, Jaybot said: I use the Dremel 290. You MUST buy yourself vibration absorbing gloves! The vibration can cause nerve damage... permanently. I use gloves made for jackhammer use, here's a pic of ones like mine: Yep, for sure and for certain. They're kinda thick, but they do the trick. 1 Link to comment Share on other sites More sharing options...
Ludwigia Posted February 16 Share Posted February 16 14 hours ago, FossilFamily_24 said: rather the best way to go about working on it (method, tools). If you scroll back up to jpc's contribution, you can read about the easiest and surest method to go about this. If the sledge hammer is too heavy for you then use a club hammer. He and Ptychodus04 are the most experienced preppers who are participating here. I would recommend you just follow their advice. 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
citronkitten Posted February 16 Share Posted February 16 On 2/16/2024 at 10:42 AM, SPrice said: Yep, for sure and for certain. They're kinda thick, but they do the trick. I need to get a pair of these; wasn't using them before as I wasn't sure if I needed them for hobbyist use, but after reading strong recommendations it seems safest. On Amazon.co.uk the sizing isn't very clear; what size would you recommend for a woman with fairly small hands? Just not sure if a medium would be too large, as that seems to be the smallest that a lot of brands sell (again, UK Amazon). Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 17 Author Share Posted February 17 10 hours ago, FossilDAWG said: If it's from Illinois, I don't know what is in it except it's not a crab. Marine rocks of the appropriate age (Jurassic to recent) do not occur in Illinois, and no crab concretions have ever been reported from that state. That concretion seems very large for a Mazon Creek type nodule as well, but who knows? Don Yeah, I learned the crabs found were horseshoe and not true crabs. Link to comment Share on other sites More sharing options...
FossilFamily_24 Posted February 17 Author Share Posted February 17 Thanks everyone! Link to comment Share on other sites More sharing options...
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