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Like the title states, let's see your results with acid prepping! I have found not as much info on this style of prepping, so please feel free to give some details as to how it was done, i.e. time, technique, soak sessions, etc. Have a great day everyone~

Hello. I was wondering how to make from sylvania OH Brachiopods with pyrite shine. Because i have some that have pyrite but are covered in matrix and are not sparkling the same way that ones that have been treated with acid. Thanks! Trilobites_are_awesome.

Just came back from a fossil hunting trip at the Aust cliffs (uk), I found some of the rhaetic bone bed and wanted to use acid to prep. Is there some type of vinegar which will work? Thanks for reading

Ciao a tutti ! I wanted to have some information about the use of chemicals for the preparation of fossils, let me explain better. I'm currently in my second year of PhD in chemistry and I have a wide range of chemicals, bases, polymer acids etc. My question is what could I use for example to clean the limestone matrix compared to the classic diluted acetic acid? is there anything better that maybe I could have in the lab? I had thought of some stronger acid but I'm afraid that using something stronger could be detrimental to the fossil itself... Grazie !

Hello all, Me and my friend would like to start practicing chemical preparation. Neither of us have done that before. We were mainly wondering what types of commercially available fossils are fit to practice this on? I know of limestone fossils like Keichousaurus, but that seems quite expensive for a first try. Neither of us lives close enough to a fossil location to reallistically obtain this way. So I tried to make a list of items that are not too hard to find unprepared. My friend has quite a bit of experience with working with chemicals, but doesn't know what chemicals would work with what rocks. It has also never been my strong side. Do you think chemical preparation would work on any of these fossils? -Schlaifhausen ammonites blocks -Khouribga fossils (don't think I've ever seen chemical preparation on this) -Spirifers from Barvaux, Belgium (been here a couple of times so have quite a few of those) Would love to hear more suggestions if anyone has any? We do not have the room to afford the other tools for mechanical prep, hence why we want to try it this way.

Hello, forgive me if this question has already been answered. I found dozens of crinoids this last fall. They look great when wet, but when they dry they're dull and dirty looking. I've tried soaking them in soapy water and scrubbing with a toothbrush, but nothing spruces them up. I've also tried using vinegar given that the limestone doesn't fizzle, but it destroys the crinoid. Is there anything I can do to brighten or clean these things? The last two pictures are the crinoids when wet and the first is dry. Thanks for the help.

This question should probably go on the general discussion, but I post it here on the chance that the answer might point at some form of fakety. I am intrigued by this K. being offered fo sale. How was it prepared? To my untrained eye, there seem to be no signs of tools. Judging by the areas surrounding the fossile, it would appear that some kind of acid (?) has been used, thar corroded the stone matrix away while leaving the bones intact (?!?) Is something like that possibile?

I have read the bits here and elsewhere about DMSO. I'm not that serious and I'm not sure that's what I'd want anyway. Being new and my first post, I hope it's in the right place. I have some sandstone which was a big clump. Fairly beat up from being in Lake Michigan. I looked and decided to crack it open and see what's inside. Now I have a few pieces and I see some interesting fossils, but they look like the same material, nearly, as the surrounding sandstone. I can only guess that if I try to dissolve the sandstone, I'll probably also dissolve the fossils? These look like shells or outer shells of assorted ancient sea life. With a smaller chunk, I've been putting it into a campfire burner two nights after the fire is going down. I figured heat cracked rocks from archaeology why not try some baked sandstone? Here's a before which hopefully will show what I have. I have some tools, chisels, and a couple of old dental picks. I'm not sure if that's the right way to go. And I wonder if some solvent, over a period of time, sitting out in the garage, might work on the sandstone? Again the acid idea doesn't seem like a good one, whether it's Hydrochloric acid or acetic or something else, the fossils seem like the material is too similar and I'll just end up with a bucket of mush? Anyone with some experience have a starting point to share? Thanks

Hello, I'm looking at this ~5cm Ohio Silica Shale Paraspirifer bownockeri. I was wondering if such bright gold coloration indicates "enhancement" of the pyrite by harsh prep, acid treatment or brass wire brush? Or is this just the natural color of some specimens? Many pyritized Paraspirifers I see are more grey or silvery (though I have indeed seen such gold ones). Other pyritized fossils as well seem to typically be more the silver/grey color, and as far as I can tell Pyrite itself is generally paler than a vibrant gold. Thanks.

I am writing a short manual on preparation methods for our club and I am including a short section on chemical preparation. This is most commonly done with acids on carbonate rocks. For many newbies, chemical preparation is attractive since all you need is a weak acid that everyone has in their kitchen (vinegar or lemon juice) and don't have to buy expensive equipment. I try to avoid it if at all possible since it works on a very narrow class of matrices, you have relatively little control over it, you may dissolve the fossil itself if it hasn't been silicified and its irreversible. Consequently, I don't have much experience with it. I have tried brushing Muriatic Acid (concentrated HCl) on limestones and immersing them in weak acids like household vinegar with mixed results. I have a few questions: does acid preparation only work on carbonates (limestone CaCO3, dolomite CaMg(CO3)2 or siderite FeCO3) or are there other fossiliferous matrices that can be prepared using acid? Are there other legitimate ways to prep using acids other than brushing it on or immersing a fossil in a weak solution? I am aware of using organic solvents to prepare tar pit fossils, but this is something outside of most amateurs. Are there other chemical preparation methods other than organic solvents on tar pits or acids?

Many of the fossils collected from the Bighorn Basin are coated in this nasty purple-ish carbonate material. I've tried soaking it in a dilute acetic acid but it's not very effective. Would dilute muriatic acid work? Or would it react with hydroxyapatite?

Hello community, A friend of mine recently gifted me this keichousaurus. But as you can see the Preperation is not the cleanest/nicest. Can I as an amateur fix this by myself or make it look cleaner and nicer? I also had the Idea that I maybe could work from the other side with Acid layer by layer. Then I could also be able to see the upper side of the specimen rather than its belly. Or would that not work/ be to risky? Isbthe rock maybe to thin? Can i as an amateur who never worked on a fossil with acid before make that or is it generally not possible?

This could possibly be a random incoherent thought bubble, but here goes anyway. I was reading another thread which mentioned acid prep as the way to go for a particular item and then was proceeded by a bunch of professional preparators (that I repsect) being scared of the prospect of attempting it themselves. This really bothered me. I know I have a wealth of experience preparing far surpassing what a normal fossil aficionado would have, and I have always thought of acid as a tool in my bag and not something to be scared of. I am not a professional preparator, though I may be as close as one could be without being one. Absolutely it takes knowledge and safety and time. But it is no reason to scare our community away from it. Some of the best specimen have been prepared this way. There are two instances where I have used acid extensively. 1. Pennsylvanian stromatolites containing terrestrial vertebrate material. (Hamilton quarry in Kansas) 2. Brazilian fish nodules. Given exposure to other materials, that list might expand quite a bit but I generally stay in the lane of terrestrial vertebrates. My studies were generally only in that area. The setup is simple. 1. Make sure you are working in a ventilated area. You either need a lab hood or a private outdoor location (I do have the benefit of living in a sparsely populated area, my preference was to build a 'covered' workbench that holds several acid baths). 2. Protect yourself, wear gloves and a mask appropriate for your acid. I generally worked with 10% acetic. Note: Test, test, test, find practice pieces to get your exact acid strength and boundary agent defined. 3. The process is daily and repetitive. Don't do acid prep while you are traveling/not home. 4. Coat exposed fossil in acetone & polystyrene mixture or other appropriate material (you are creating a boundary between the fossil and the acid but not the matrix you want to remove). 5. Drop matrix in acid bath. 6. Remove matrix daily, wash and repeat 4 & 5. 7. Stop when you are happy. Please professionals, correct me where I am wrong. In my opinion, anyone who has done a chemistry 101 class should have the skills/knowledge to do acid prep. A few google searches should fill any holes that are lacking. Absolutely choosing the right acid for your particular piece takes some research, but it shouldn't be something we are scared to attempt. Absolutely safety should be first. Absolutely you should have practice pieces before attempting something major/important. I don't think we consider acid preparation enough, myself included, My default is mechanical removal followed by air abrasion. But when we have a case that screams acid prep, we should have the tools, knowledge, and expertise(and probably some technical forum thread) to deal with it. If we aren't using this forum to document our techniques and expertise for the next generation of preparators, what's the point? I learned from Orville Bonner at KU in the last few years of his working life, he may have trained 5 other people in his lifetime. How is that advancing our field? I think it is barely sustaining the practice. The knowledge will disappear if we do nothing. Currently, I work as an IT architect. My job is to listen to the needs of a project and find the appropriate solution. Fossils are no different. We all want the answer/solution first, this is the current society/culture: immediate gratification. We need to remember to listen to the needs of the specimen, have the wisdom to choose the right solution, and the knowledge to perform the proper technique. Please add your thoughts and experience. P.S. I may have inspired myself to 3D acid prep some Brazilian fish this summer.

Okay gang. Don’t ever do this. Brachs are so common here ( along with crinoid bits) I use them as aquarium gravel... But, here’s what happens when you figure out how to acid prep Kewitz limestone to expose calcite and not loose morphology: I finish these with a week long silicon oil soak to make them shine.

So, what is the safest way to remove matrix (sandstone and limestone) from calcium shelled fossils. Everything I've read involved acids (some pretty dangerous). What is most ecologically friendly and safest way? I have picks and dramel , but these shells are very thin and almost impossible to remove from the matrix. I am thinking that weaker acids might not work that well and the costs of using more powerful stuff would require a special room with exhaust systems and ways to neutralize the stronger acids to make them environmentally safe. Images are typical of fossils I want to extract. Anyone have a good solution for this issue?

Here are 2 more Halysites 'chain coral' that I found in the Silurian of Wisconsin. The rocks were soaked in diluted muriatic acid for several hours, to partially dissolve the matrix and reveal the chain corals.

Central PA, Mifflintown-Bloomsburg (undividied) Block collected from roadsite float. Its pretty variable, with a flaky/fissile layers alternating with slightly more cohesive ones. Lots of broken brachiopod bits. For an experiment to I dropped an unremarkable flake the size of a large coin in some vinegar and let it soak for a day. The flake had a couple brachiopod bits and I wanted to see if they would fall free or dissolve in place. The brachiopds disappeared and I was left with this (see pics). Of course I got really excited and thought I had an early fish spine, but now I think I dissolved a crinoid stem and what we see is the matrix that filled in the soft bits. What do you think? Total length is 3/4"

I have zillions of rocks/shells/fossils/pieces of bone, etc. I am not a chemist, and I do not want to get into anything unnecessarily dangerous/toxic. Also, I would love to possibly cut and polish rocks that I find fascinating. What do I need for my “starter kit”, and can you/will you please recommend sources for these items that you work with, and that you like and trust (especially a source with great patience to answer the tons of questions I will have). Thank you- Karen

(Not sure of the tags I should use.) This is the first instance I've found of any sort of 'bloom' on a fossil in my collection. Luckily it's not the best specimen but it is an echinoid and they are not as easy to find here as in some other places. Sandstone from the Haslam(?) Fm on Vancouver Island. Is this a calcitic bloom from some sort of acid or off-gassing from something in my storage media? I'm not sure how long this has been in this condition but I think it's happened within the last 10 years. I'm trying to keep things away from my collection that might cause this sort of thing. I've got wooden (not oak) cabinets, and the little white fold-up boxes with cotton or cloth substrate. I'm trying to get rid of plastics, foams or anything else questionable, and I can't think of what else there might be that could be a problem, unless simple humidity in the Summertime will do it. (This is indoors)

Hi Fossil Forum, I've recently picked up a unprepped skull of Captorhinus aguti, from Olkahoma and am looking to do some further delicate prep. I've not used acid preparation before on such a delicate specimen (such as Muriatic acid) - could anyone who has give some advice about application, duration and dilution levels? Many thanks Tom

Hello, Long time occasional lurker, first time poster; I hope this is the appropriate place and method for posing this question, and I apologize if it is not! I have some limestone blocks containing conodont teeth and shark teeth, which I would like to break down with acetic acid. From what I have read, adding a buffer to the acid solution would greatly help in preventing damage to the teeth (and especially the roots), but I have no idea what buffers are readily available (and from where they would be available) and commonly used (and how much is needed). Can anyone advise? Any experience you've had with buffering acetic acid for dissolving limestone matrix to retrieve small teeth that you'd be willing to share would be greatly appreciated! Much thanks! :-)

Hi this is Matthew my question is can you use acid to clean fossils and what kind should I use ? and does anyone know how to do it correctly ? and thank-you