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Showing results for tags 'slab'.
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I have this specimen sold as fossil wood (without other info) in my collection. The shape and circularity of the visible rings of crystals could confirm this, but actually I'm not sure about it- I'd like to hear the opinion of some experts. Thanks in advance.
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Keicho - no shoulder blades, no pelvis...?
Ezio Bonsignore posted a topic in Is It Real? How to Recognize Fossil Fabrications
No shoulder blades or pelvis are visible. Just a matter of presentation/preparation, or someone sort of forgot such annoying details while carving/painting a fake?
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I cant exactly identify but is this the armoured plating of a sauropod?
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Hello to all. This is my collection of flora from the Carboniferous period. This topic will be filled gradually - there is a lot of material. All material originates from the Araukarite Formation of the Gzhel Stage of the Upper Pennsylvania Carboniferous period (303.4 Ma). Unless otherwise specified, it means that the default sample is from this formation. The type of substitution is silicification (sometimes with ferruginization), sometimes with quartz crystals on the surface of the samples. Enjoy watching Part 1. Sample 1. Part of a branch of small diameter with a whorled arrangement of knots. VID_20211212_143605.mp4
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Hi. I work in a garden centre. We have spotted this on one of the slabs we sell and we were wondering if it was a fossil. If so, what is it?
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When faced with a radiodont appendage fossil; How does one effectively determine which slab contains the "part" or "counterpart" ? For reference, here's the holotype Pseudoangustidontus appendage. The first pic, Figure A, is apparently the positive(?) "part" of the fossil. Whilst the second pic, Figure C, is apparently the negative(?) "counterpart". Like it's easy to tell the difference between an impression/cast, or the actual fossilised remains for hard-bodied specimens like shells, exoskeletons and bone. But for some soft-bodied organisms, it's especially difficult when both slabs seem to preserve both the impressions and the fossilised remains of the organism, as in the case with the Pseudoangustidontus holotype. I've also heard that concavity of the matrix usually helps in identification; but thin and soft-bodied specimens often just leaves a planar imprint, so judging by relief might not be too reliable either. Any thoughts on this matter?
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Low-cost approach polishing small carbonate rocks and fossils by hand
FranzBernhard posted a topic in Fossil Preparation
Some of you may have noticed my flat polished fossils and fossil rocks. A few of you have some of them in their hands, e.g. @ricardo, @taj, @Monica, @fifbrindacier, @marguy I lost access to the cutting, grinding and polishing facility recently. No great loss, but I still have some small specimens that I want to have polished. What to do? I tried a low-cost, low-effort approach, using things I already have. 1. Cutting: I tried to cut some small specimens with an angle grinder. Well, it worked, more or less. Not the best option, don´t to it. Better would be a tile saw. They are cheap, far less than $100. But this is nothing for an apartment, I think. Getting a somewhat flat surface is the biggest problem of this low-cost approach. But see below. Everything else is done on my usual desk! 2. Coarse grinding: No grinding machine here. I usually ground things flat on a diamond disk, followed by hand grinding with loose 600 and 1200 SiC (silicon carbide) grit. But I know, that limestone can be ground rather quickly by hand with SiC. Being on a low budget, what SiC should I buy? I bought SiC grit 400 (1 kg Euro 10.80,-) and SiC grit 1200 (0.5 kg Euro 14,40,-) from an Austrian supply house. What grinding plate should I use? Usually, steel plates are used. I don´ have any. But I have some glazed tiles. I was really surprised how well this worked. The SiC seems to be of very good quality and very "aggressive". A grinding time of to up to 10 minutes was enough to remove even bad scars from cutting with the angle grinder. Based on this experience, I tried to grind a small Favosites specimen without prior cutting. Worked very well, I got a flat surface of several cm2 within 10 minutes. 3. Fine grinding: I used the same tile, cleaned it thoroughly, as well as the specimens (running warm water, brush). Only 2-3 minutes necessary to grind with 1200 SiC. Grinding worked well, but specimens had some fine scratches. I am not sure if this comes from outbreaks of the tile or if the SiC has some coarse grains admixed. Will try the bottom of a stainless stell pot instead of the tile. Seems a good option, but you should not be allergic to nickel... 4. Polishing: I have usually done this on a rotating felt disk, it took only about 1 minute for small specimens and up to 10-15 minutes for quite large specimens. Some years ago, I used a piece of jeans fabric for polishing a small piece of jet by hand - worked well. I scaled it somewhat up. Used the leg of a jeans, put a tile for some stability in it. I purchased Alumina for polishing from the same supplier (0.25 kg Euro 18.00,-). It works really well, but it takes some time, about 10 minutes for small specimens, about 20 minutes or even more for somewhat larger specimens. And don´t forget to clean your specimens after fine grinding! 5. Result: Quality of polished slabs is as good as usual (except some small scratches, not visible to the naked eye), but it takes much longer and large specimens would be a real pain. 6. Costs: No hardware bought. Purchased amounts of grinding and polishing medium will last for at least 100 specimens. So costs are less then 0.5 Euro per specimen. Summing up: If you like to make a few small (< 5 cm) polished specimens of carbonate rocks (with fossils or not) or also e.g. jet, you can do this easily by hand on your desk with things you may already have at home. You need to buy some grinding and polishing medium (see above), though. And you need a somewhat flat surface to beginn with. Either naturally or a saw cut of some kind. First row: Coarse grinding with 400 SiC on tile. Second row: Fine grinding with 1200 SiC on tile. Third row: Polishing with alumina on jeans leg. Fourth row: Final results. To the right the specimens polished during the last two days (besides all my other commitments). Franz Bernhard
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I've never put much time into sectioned and polished fossils, usually just because I don't usually collect material that would look well cut over whole. While preparing a trilobite I collected in Illinois over the Summer and I was cutting sections off the matrix bottom so the matrix lay flat as a stand. To my surprise I ended up cutting thin sections through a Favosites coral that piqued my interest. Coincidentally, this was at the same time @FranzBernhard posted his thread demonstrating a low-cost approach to polishing and sectioning small carbonate rocks and fossils by hand. With such a handy guide put forward at a perfect time I decided to try my hand at sectioning and polishing fossils. I was waiting on grit polish in the mail for a while and that has now arrived which allowed me to finally try some sections myself. I figured I'd post the humble results here so as to encourage more people who might be interested in trying this. I've cut lots of rocks before but this was my first time attempting polishes. The uneven cuts from some of the specimens are noticeable in the polish. I tried to grind some of the surfaces even before polishing but this was more difficult for the hard material. Oh well. I think I can improve the fine polish on a lot of these by putting more time into them but I think this was good as a first attempt.
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I’m laying these natural sandstone slabs today and there ment to have fossils in them there noticeable bits wondering if anyone could help tell me if they are and maybe what they are thanks in advance
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I have this little slap I polished a awhile ago, it has some really interesting critters on it. Even a micro jaw bone with teeth maybe? Has many interesting things on it, I have just taken pictures of a few. Green arrows point out the "jaw" and a few other things. The "jaw" is the biggest at a whopping 40mm.
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Hi All, I recently purchased this Glossopteris slab. It appears to be made up of multiple layers showing fragments of leaves Would any further prep reveal more detail or possibly entire leaves? Thanks
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Lulworth is a late Jurassic to Mid Cretaceous area.
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Let me know if you need anything else to help. It's rad! This thing is soooo heavy!
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I framed a pair of rock slabs recently, using a technique suggested by a forum member. I've done this before, and it has always come out well. I used Neilsen Metal Sectional Mouldings for the frame. I got the pieces custom cut by a frame maker, and just had to screw them together and add the wire. This technique works for slabs are fairly square or rectangular. There is overhang on the frames with will let you fudge a bit unevenness, but there is a limit. Neither of these slabs were perfectly rectangular and they worked fine. I used the N117 size frame, because it gives decent depth for the thickness of the rock slab and is also has a slim edge for these small slabs. I have use the N95 frame also; it is good if you want a thicker frame, such as for a large slab. Total price including shipping and hanging hardware for both was $26.61. Send me a PM if you want to know the online frame shop I used.
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Can anyone help me identify the vast array of specimens on this slab? I see some rugosa.
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From the album: Marine reptiles and mammals
Close up of the stomach contents-
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From the album: Marine reptiles and mammals
Cross sections of the stomach, full of squid/cephalopod hooks and beaks, of an early Jurassic ichthyosaur (Stenopterygius quadriscissus). One slice has the animals ribs, the lighter tan objects, around the stomach, while the other is entirely of the stomach contents. -
From the album: Marine reptiles and mammals
These are the reverse sides of the slabs -
It has been a while since I have been online. So this is one of those very unhelpful posts where I know very little about this fossil's origin. It was purchased in South Africa and the slab is very well preserved. I am hoping this is not a fabricated fossil because the detail is exquisite. This is also a chance to show off my new Nikon D810 camera. I will answer any questions to the best of my ability.
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I helped one of my friends make a hanger for his huge Ohio hash plate. I guestimate it weights 15 pounds. I learned this technique from Harry Pristis, and only slightly modified it from what he posted. I used two steel rods from Lowes, and two turnbuckles from Home Depot. The materials cost was about $10. I used a wire bending jig to create two W-shaped "hangers" as shown. This jig was one like this; costs about $5. I bent the end of the hangers over to hook onto the plate. I used two turnbuckles to attach the rods together- and screwed them tight. I probably could have used wire, but wanted to be sure it would never fall.
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So this is my second fish post of the night. Just wanted to know what this guy was, and the time period it may have come from. Thank you!
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Harry Pristis pointed me to this method, so I thought I would show how it worked out. This only works with fossil that are fairly rectangular or square. A little deviation is okay, depending on what frame you choose. I used Nielsen sectional aluminum picture frames. https://www.nielsen-design.de/en-EN/products/frame-mouldings-aluminium/ They come in a wide variety of colors and styles. When I bought a frame, I told them the exact size of the slab, and they added a tiny bit when they cut it, so the slab would fit inside. So, check with the seller to see if you are ordering the exact size of the slab, or if you need to add a little length yourself so the frame sits inside. I recommend using a carpenters' square when measuring, it made it a lot easier. You need to make sure the frame you are ordering has enough overhang to cover up any potential gap between the slab and the frame. I chose the N95 frame which has about a 1/3 inch overhang. There are frames with an overhang closer to 1/2 inch if you have an irregular slab. You need to make sure the frame you get is deep enough for the thickness of the slab you get. The N95 frame is about 1" deep. Here is what the N95 frame looks like: There are steel angle brackets you use to screw the frame together; here is one of mine seen from the back: You add steel spring clips to press the slab against the front of the frame; I did not use glass: Now, you can use wire to hang the picture; I decided to use the nielsen security hanging system instead; this locks the picture against the wall. It can only be removed with a special tool. So, if someone bumps against it, it won't fall and shatter (or be stolen). They cost me about $4.25 for one set. HOWEVER, I will say removing them with the tool is really annoying, so if you use these I hope you won't need to take them off for a long time. Here are the brackets for my small one installed; it has one hanger up top, and the "lock" below. On my larger slab, I used two hanging brackets up top. So, here are how they look finished: I know we aren't supposed to post retailer's names here; if you want to know where I ordered the frames, send me a PM. These can be ordered at a lot of places online though. The prices for the small frame and all associated hardware, including the locking hangers was $15.30. The price for the larger frame and all associated hardware including locking hangers was $20.46. Shipping was $11.65. So far, I am very pleased with this method, and would like to use it again. Thanks to Harry for the tip!
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I just got this slab in the mail today. Overall I am SUPER thrilled with it. It had been advertised as a pair of Crinoids on a slab, but it looks to me like there is a possible third Crinoid that might be even bigger than the other two still lurking in the matrix. There might even be a forth one, and it looks like some possible trilobites scattered throughout. I am newer to prep work (and fossils for that matter), but this looks like it has the makings of a really neat plate. My questions would be if you think I am right in my assessment of the plate, and also what steps for prep work. I am getting into it more, but I am thinking of trying to find an expert to take care of this one since I really don't want to ruin it, it is really nice as is. As a side note, on one of the prepped Crinoids there is a trilobite wrapped up in the stems! I don't think it needs more prep, but still thought I would mention it just since it is neat!
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This was given to me as a gift many years ago. Its the only fossil I have that I didn't collect myself. I know nothing about it its age or where it was found, or if it is possibly a fake. If it is to stay in my collection, I want to have a good ID and if possible a fairly accurate location and strata.
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From the album: North Sulphur River 160529
An iron-replaced hash of bivalve and other broken shells.© Mitchell Moore
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