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Showing results for tags 'blackened'.
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I would really appreciate any help identifying this (possible) fossil. My son found this blackened subject while he was digging on the beach of Texel, The Netherlands. It’s approximately 70mm long and looks fragmented, heavily eroded and feels solid. There’s a small hole in the top middle (approximately 3mm). Any help is greatly appreciated!
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What's covering my plesiosaur vertebra? How to clean
pachy-pleuro-whatnot-odon posted a topic in Fossil Preparation
Hi all, I recently decided to buy the below plesiosaur vertebra after having seen it for a long, long time. It dates to the Callovian of the Oxford Clay and was found at Peterborough. I suspect it may be attributed to Muraenosaurus leedsi, as it comes from a cryptoclidid plesiosaur, but is both larger and more elongate that the typical Oxford Clay Cryptoclidus vertebrae I'm familiar with. Supposedly coming from an old collection, it has a blackened exterior that doesn't cover the entire piece, with the more common buff colour visible underneath. As such, I expected the dark colouring to be simple dirt or may be some kind of consolidate that could be removed using acetone to leave a nice and clean looking vertebra in its place. However, since having tried acetone cleaning, the dark colour doesn't come off - suggesting that it isn't surface dirt and any consolidate, if present, is not soluble in acetone. I've also noticed that the black colour doesn't spread equally across the vertebra, which is most noticeable towards the top on the front face (first image) where one half of the vertebra is buff, the other black, with a hard separation in between. As this mottled pattern can be seen in other places on the vertebra as well, I thought that, may be, the vertebra might have been in a fire and have become covered in soot. I find additional support in the latter hypothesis in very brittle pieces of bone in one or two spots, with a charcoal-like grainy texture. Lastly, then, I've spotted a tiny edge of yellow staining/infill in an area where the vascular structure of the bone is exposed, with some white infill in an area adjacent - which I've now started worrying might be pyrite. My questions to you are: Origin of the blackening: Does the black clouding of the vertebra look like natural preservation? Related to the above: could the black clouding be due to pyrite decay? In contrast: could exposure to fire cause the clouding pattern seen on the vertebra? What consolidate might have been used to result in such colour patterning? Cleaning: Is there a way to remove soot from a fossil? Has anyone tried? Other than removal by acetone, what other ways might I try to remove an old, darkened consolidate? In case of decayed pyrite, I don't think there's anyway to clean the surface, other than, may be, through careful sandblasting, is there?- 57 replies