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Showing results for tags 'rock'.
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Vince San Antonio, Tx I walked over this piece for weeks. I thought it was a piece of bark or mulch. I picked it up and washed it off like a rock. After I dried it off I noticed the burn looked odd.
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Low-budget rock and fossil cutting/slicing/slabbing
FranzBernhard posted a topic in Fossil Preparation
Ok, I proved it possible to make polished slabs of substantial size (ca. 50 cm2) without any machine, purely by hand, in an acceptable time and of good quality and with things I already had, especially flat plates. Grinding and polishing media had to be bought, of course. All of this can be done on a desk in an apartment, no serious noise or dust production involved, just some sludge . Only one problem remains - you need an as flat as possible surface to start with. Such flat surfaces are usually produced with rock saws. For rock cutting, I have only experience with professional equipment. However, such rock saws are expensive, heavy, noisy etc. What are the low-cost options for the occasional saw cut? First, forget the angle grinder. Second, what about tile saws? They are cheap, around 50-60 Euro, and far less than that for a used one. Quite lightweight and portable, about 10 kg. But they are made for cutting thin tiles, maximum cutting depth is about 35 mm. I am used to "rotate" specimens on the saw blade, so this can be doubled (Attention, this rotation can be dangerous if not done properly and results also in a surface not as flat as you might desire!) I don´t have experience with a tile saw yet, has anybody of you? And has someone used such a saw in an apartment? Has anyone tried to make parallel cuts with such a saw? Other thing: What about cutting specimens already in the field? Has someone done this with low-cost equipment? Maybe you can use a tile saw with an DC/AC converter connected to your car? I think, that´s all what I like to know at the moment . Thank you! Franz Bernhard -
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- 19 replies
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I've reached out to the state geological survey and a couple gem clubs without luck but need help in identifying this rock. Any help would be great. The rock is much lighter than it looks and seems to be fairly fragile.
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- cobble
- missouri river
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check out these worm trace fossils found in the creek today
matthew textor posted a topic in Fossil Hunting Trips
Hi everyone this is matt again check out this worm trace fossil I found in the creek today here is a photo -
Found this over the weekend at Caspersen Beach. Grabbed my attention immediately with the beautiful color and design. Not sure that any fossils stood out, but maybe I'm looking at it wrong or just focusing on the wrong areas.
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- beach
- caspersenbeach
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I wondered if anyone might be able to help with this oddity. It's about 4-5 cm long, and was found on the beach at Wells-Next-the-Sea in North Norfolk, UK. Exciting dinosaur brain? Mundane piece of flint? Put me out of my misery, please!
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Found slightly north of Columbia, SC in the middle of the state in a creek. Caught my eye because of the inside, but the outside seems to have some sort of non-natural looking inclusions. If you’re able, zoom in on the exterior to see what I mean. Any help is appreciated! Totally understand this could just be a rock but it seems too odd.
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Wasn’t really sure where to put this but thought it was worth sharing. A couple days ago I found this concretion and then I decided to paint it to try to make it look like 5 dinosaur eggs (only a lot smaller, they’re all under an inch long). I’ll probably add to this with more rocks with fossils painted on before, After,
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- art
- concretion
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Hunting today. In an area which I had not previously found the rockfossil mix, I found many of them. Here are my most interesting. Here is one , which I believe is whole, where I think I know the genus, and likely the species. looking for confirmations... This is a miocene fossil ... 5 - 23 mya. And # 2 is a broken tooth, Once again miocene fauna. and finally, one where I have no clue... This is an oddly shaped bone.... I am seeking the most basic clues. Which bones look like this one? As always, comments, suggestions, identifications are ALL appreciated!!!! Please do.
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My dad found this rock in the Vermillion River in Illinois last weekend during a camping trip. While my dad insists it's a petrified toe or a toe that was possibly covered in mud then compressed (or something of the like???? I'm not quite sure...), I personally think it's just a rock. Can someone please help officially determine what exactly it is? Thank you! -Abby
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Hi! There is a rock with fossils (?) my house. It's from my father, passed away about 10 years ago. I don't know what it is, but maybe it's from his China travel. I have searched some images of old sea animals fossil, but still don't have a idea. Is there anyone explain them? Thanks!
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My father lives in SE MN, south of Rochester. He lives on a farm on top of a hill and has been doing a lot of topo work. In doing so, he has discovered that almost every rock he picks up has what appears to be seashells and fossilized plants in them. His research led him to conclude that the fossils are in the range of 400 million years old. The other day he was walking his land and saw what he thought was a potato sticking out of the ground. He picked it up and was puzzled. It feels hard like a rock, is smooth, and most shockingly it glows when light is applied to it. Is this an egg of some sort?